Hi everyone I created an account on the forum ages ago but this is my first post, I hope I am doing everything the right way, if I am not following the correct procedure please let me know. Don’t want to start off on the wrong foot. This place is a wealth of knowledge and I hope I might be able to help add a little bit to the community in the future. I am an owner/operator of a small fleet of machines and I do almost all of my own repairs and maintenance so fingers crossed that I can be helpful to others on here as well. Anyway on to my question! So I have a series 2 D6H LGP dozer that I have had for 4 years and have had over heating dramas (engine and trans) ever since I have had it. As we have worked through everything we have been getting it better over time. We thought we finally had it all sorted but as it has heated up here in Australia (our summer at the moment) the dozer is again getting hot, engine only now. I was helping a friend with his d6h the other day chasing an overheating drama as well and he had been told about this flow restrictor in top radiator hose. The story was that this was part of specing the dozers for cold climates and that it could cause over heating in hot climates and it should be removed. It wasn’t the drama with that dozer but I am pretty sure mine has one as well (going to check in the next couple of days) and I wonder if this could be the final drama with my machine. Has anyone seen these restrictors before and is there any truth to the cold climate spec up story? My 966G loader definitely doesn’t have one so I had just assumed it must have been a dozer thing, couldn’t work out the purpose though. Can’t find anything about it on SIS or anywhere on the internet, so I am hoping someone can shed some light on it for me. My serial no. Sn: 4GG05795 Best regards Jason
By the fella in the pub I suppose.? TBH I've never heard of it but that doesn't mean much. Why don't you just remove the top radiator hose and take a look.? That would remove all doubt. Is this the only D6H you have.? What sort of work is it doing and how do you go about cleaning radiators.? What coolant do you use.? A list of what you've done so far to improve the situation might also help. Oh, and some photos as well, but you will need to make a minimum of 3 posts on the forum before you can upload them.
I don't know CAT's but I've never heard of such a thing, and I know cold climates and heat flow. It doesn't sound impossible that something like that would have been made, just never seen it. The temperature drop across the radiator should tell if something like that is contributing. Work until it's borderline overheating, take the temp of the coolant going to the radiator, and coming back. The top and bottom of the radiator work as long as they're painted surfaces, or the ports on the engine.
Hi guys thanks for the responses. I only have the one D6h, I do have a D6C but it’s not similar enough to test against I don’t think. Haha yeah Nige almost… the mechanic that rebuilt the engine in the friends dozer before he purchased it. There had already been some conflicting stories from him so I wasn’t sure if I should believe it or not!! Apparently the restrictor could mean an extra 5*C. The restrictor was definitely there on that dozer though, the friend said make the hole bigger so we did. I forgot to take a pic of it but I will if mine has one when we check the thermostat tomorrow. We couldn’t tell for certain how much of a difference it made because we replaced plugged coolers at the same time on that machine. The restrictor was in the outlet from the thermostat housing and reduced it from full size back to a bit over about half size if I recall correctly. Wish I had measured it, will on mine if it’s there. Anyway yeah cleaning radiators is a huge thing for us, same as air filters. We struggle with fine red dust especially on the dozer. They are usually blown out with compressed air daily or every couple of days if the conditions are better. We wash them with a steam cleaner every chance we get if they need it. The dozer has been sitting at the job for a couple months and is a long way from base so we took a water tank and Honda water pump to it the other day to flush it out. It’s not perfectly clean but it’s not enough of an excuse either. It is running green coolant. I took pics of the temps after flushing but before I changed the fan belts (which were worn out). So I’ll take some more temps as well tomorrow. I think there was still about a 4*C drop from top to bottom but will confirm. Top hose was around 104*C. The temp of the afternoon was 44*C so anything will be warm in this weather, but I thought if there was any truth to the magical 5* cooler it would be very helpful. The dozer is pushing an 18ft stickrake clearing fence lines and fire brakes on a cattle station. So it is traveling forward pushing a lot more than reversing. I will do another post of a list of what we have done on our journey to getting the dozer cooler so far. That should hopefully get me three posts and let me post pictures.
In hot air temps like that, airflow is critical, and that's a tough job to keep a radiator clean. Soaking with detergent, rinsing and repeating are needed to get dirt out. Or remove the radiator, or coolers in front to get better access and rinse until clean. Pulleys wearing out will cause slip and wear the belts faster also. Are you running 50/50 coolant, and has it always run that? If it's had water added, then there's the possibility of mineral deposits blocking the radiator tubes. You might check into 40/60 or even 30/70 coolant mixes, water moves heat much better than glycol, but you'd have to change the coolant sooner just because there's less of it. I'm still suspicious of the restrictor. I'd love to see a picture and location. I don't think it's a significant factor in the overheating though. edit: It turns out coolant restrictors are easy to find, either washers or thicker aluminum pieces to do just what you say, restrict the coolant flow. I assume for "high performance" use without a thermostat. I don't see a purpose for one with a thermostat in place, and you'd never want to run a diesel without a thermostat, nearly all have a bypass that the thermostat has to block off.
When you go in there take a good look at the thermostat and post details of it. If you find the famous restrictor have a good look for a Part numbetr on it in addition to taking photos. Do you dilute the green coolant yourself from concentrate or buy it premixed.? TBH I'd suggest switching to Cat premixed Red ELC whatever your answer is. 4*C difference from top to bottom of the radiator is waaaaaay off, even in 44*C ambient temperatures. You should be looking for somewhere close to 10. Have you done any more work on the fan drive.? Pulleys, tensioner, etc, etc.? What sort of state are they in.? What about the condition of the fan spider itself.?
Sorry I got got dragged away from my post with list of things done so far. Ill post the list and then answer the couple of extra posts. I should have started talking to you guys at the beginning... I think you would have saved me a lot of headaches! Purchased the machine from a bloke that had got it from the auctions and said he hadn't done any work with it or on it. It looked like it had been neglected a bit but components and engine looked and sounded good. I think reading between the lines he was being forced to sell it and the 966G loader I also got as part of a package deal. It was cheap enough to take a risk on it with a budget for repairs. Dug up history on it since and engine and TC only have about 4500Hrs I think if I remember right. Engine done by Cat dealer and Torque Converter was exchanged reman. We got it home and it would run hot (engine and trans) when worked. Did an engine service. Then started off with the simplest stuff first, coolant was bad and dirty. So flushed and cleaned and flushed again ect till all seemed clean. Then refilled with new coolant 50/50 green concentrate mixed with rain water. Radiator needed steam cleaning. Ran warm but ok after that for a while, but temps slowly started going up again. Once i got the stickrake and start doing clearing jobs it was getting too hot. I blew a track adjuster and had to transport it home to fix that so while it was home we went through the cooling system properly. Found flaky rust chunks in the engine oil cooler blocking about 1/3 of it and trans cooler clean. The rust chunks were coming from the top and bottom radiator tanks it turned out. Prior to pulling everything apart the infrared gun was showing temp fluctuations all over the radiator cores so I figured the rust had blocked the cores internally and they looked a bit worse for wear anyway. Some looked older than others as well so we just replaced all the cores. Getting the rust cleaned out of the top and bottom tanks was a chore but we got them cleaned eventually and reassembled it. Swapped the thermostat with a new one.The old one tested ok afterwards when we checked it. Checked water pump. New Radiator pressure cap It needed a new alternator so fitted one with new pulley. Fitted new "aftermarket Fan belts" that made all the pulleys look worn. I only realized when I tried the old belts back on last week that the old genuine cat belts fit the pulleys better than the aftermarket ones did when they were new!!! They were on there for 400hrs but I will only use genuine belts from now on. I was under pressure to get the machine back to work and over looked this at the time, a very silly mistake. Machine went back to work and was warmer than I wanted but ok. Checked Trans pressures and they seemed to be acceptable It was ok till that summer and then got too hot again. This time it looked like the Trans was getting hot and dragging the coolant temp up. At this stage I rechecked the engine oil cooler expecting to find more rust blockages but it was completely clean. Checked for combustion leaks into coolant. Trans pressures were rechecked and things were within spec but on the low side especially the Trans lube circuit which is last in line. I reasoned that there was low oil flow to the Trans cooler. At this stage I found that the torque converter didn't have many hours, it pushed well and the oil was clean. I took the leap of faith to replace the transmission pump and that seemed to fix all the trans heating problems. All was then good through winter, coolant temp stayed at 95*C and Trans temp hovered around 100-105*C when working hard. I was hoping the coolant temp would have been a little cooler but it could keep it there. Summer again now and it looks like what we are left with is an engine heating issue. The old fan belts i put back on sit just proud of the pulleys and more air seems to be getting pushed out the radiator. They definitely made a difference but it still seems to be generating more heat than it can get rid of and when it gets up over 104*C it takes a long time to get back under 100* at high idle. I have new fan belts coming to rule that out completely but getting parts here takes a while. This left me with that restrictor removal idea and checking injection timing in case it is out a small amount. Any other ideas are very welcome, I am running out of ideas of my own.
Yeah i thought that 8-10*C difference was what i should be seeing. I don't know if that restrictor could contribute to that or not? The gap between the fan and shroud looks a little larger than it should be but lots of air is coming out the front still. I thought i would put a new thermostat in just in case that is contributing, while looking for the restrictor. Do you think its worth doing? The Cat Red ELC premixed is sounding like a good move. I found the restrictor plates mentioned with high performance cars exactly like you say but nothing about construction machines. Yes you couldn't run this engine (Cat 3306) without the thermostat because it blocks the by-pass like you said. The only use i could come up with that made sense was to add back pressure on the water pump to stop cavitation, found that mentioned where some people were arguing over whether cars overheat with thermostats removed. But if that was the reason it was there all 3306's would have it I guess... not sure? I hope my memory is right that there is one in my dozer so i can get a pic Its a 2hr drive to get to the machine so if there is any other test you guys think I should add to my list while I am there let me know Thanks heaps
I haven't checked the Parts Manual for your machine but aren't there supposed to be like sheet rubber baffles to close all the gaps between the radiator and the shroud.? There is also fluid for hot climates like yours. It's called ELI (Extended Life Inhibitor), basically it has all the chemicals to protect engine components but no anti-freeze capability because it's not needed. You could enquire at your dealer if they stock it. See attached.
If the restrictor is doing anything, it will reduce the flow of coolant through the radiator, and cause the temperature drop to be higher, because there's less hot coolant flow to keep the radiator hot all the way through. The low temperature drop suggests that the airflow is limited, BUT if the airflow is really bad, and the coolant flow is only a little reduced, you could get the same low temp drop. I'd guess that the new cores are doing their job by moving coolant well, but are somewhat dirty outside, combined with some slipping at the pulleys, combined with some air leakage from the shroud. Check the radiator with a light on the other side to see how much dirt is there, you can't see anything from the surface, unless it's completely plugged. Cavitation shouldn't be an issue if the cap holds pressure. Remove the restrictor entirely if it's a separate piece like the examples online. Check the wear on the pulleys with a small straight edge, they will get rounded out on the sides in the middle and bottom, so the profile won't look like a sharp flat bottom V, but rounded out sides. You know the coolant was bad and there was a lot of rust. I'd backflush the radiator but removing both hoses and cap, stuff a rag and an air gun in the bottom and a garden hose running in the top. When the water overflows, give it a shot of air, repeat until there's no more sediment coming out. Run it a couple hours with the coolant left in the engine and the rest filled with rainwater, drain into a white bucket and repeat until there's no more sediment. That ELI sounds like good stuff, water has a lower viscosity, higher heat capacity, and lower corrosiveness than glycol. Better all around if it never freezes there.
The only flow restrictor I can think of used on a 3306 is built on the spiggot that bolts down the temp' regulator, the bit with the 4 bolts in that is, it's used on some wheeled loading shovels with out a regulator fitted (I seem to think) it's not something I have seen fitted on a D6 anything, there is a transmission cooler air blown on the dash 2 that is regulator controlled as well as the water heat exchanger by the engine oil filter, the cooled water goes through the water pump into the engine oil cooler, then the water travels into the top of the transmission oil cooler flowing down 1 half then turning at the bottom and then heading up the other half of the cooler, after this the water enters the side of the cylinder block travelling around the liners and heading up into the cylinder head via the insert directors that are placed in the spacer plate, if you have completely stripped all the water coolers and rodded out every hole and done all the work to the Rad the temp should be running sweet, I have had to strip the head and pull the liners on engines that seemed to have been filled with dirt but this was spotted through the water hole that enters the block with the cooler removed, you could see the sludge build up. tctractors.
Sounds like water pumps were improved in 2014.
What is a "water director" on that motor?
TC has a point. If the radiator was as bad as you say it was what's the probability that the cylinder block and cylinder head are in a similar condition.? Is it worth pulling the cooler for a look-see.? From the SysOp "The coolant enters the block and flows around cylinder liners and up through the coolant directors into cylinder head. The coolant directors make the coolant flow around the valves and around the exhaust ports in the cylinder head. The coolant now goes to the front of the cylinder head. At the front of the cylinder head water temperature regulator controls the direction of the coolant flow. If the coolant temperature is less than normal for engine operation, the water temperature regulator is closed. The coolant must go through internal bypass to the water pump. When the coolant gets to the temperature of normal operation the water temperature regulator opens and most of the coolant flows through radiator inlet line to the radiator. A part of the coolant still goes through internal bypass."
My plans to get to the dozer have been put back till tomorrow now. Got stuck here at home carting water for thirsty goats today. Nige Re the rubber baffles I was thinking about the rubber strip that takes up the gap around the outer diameter of the fan, I didn't even think about rubber baffles on this machine. The way the fan shroud bolts straight onto the back of the Rad frame I didn't think they would be needed. Checked the parts diagram and they are sure supposed to be there though! Will have a go at posting the diagram. Looking at the parts diagram it seems the are set up to stop air that has passed through the Rad from recirculating around inside the engine compartment and going through again, more than actually directing the air through from the fan. Not sure on that until I actually look at the machine. It has been over 12 months since I had the Rad apart and I cant remember if they were there or not. If they are to stop recirculating of the hot air and are missing, I am thinking this could be the drama? When we swapped the belts it changed the tone of the fan and it seems like its moving a lot of air, but if it is sending hot air through again that would explain why when it gets hot it doesn't want to cool down in a hurry.... I hope its as simple as this??
Thanks TC That restrictor on the wheel shovels sounds exactly like the one we found on my friends D6H and what i recall seeing on mine. Will get a pic tomorrow if mine has one. Both machines have thermostats too. I thought it might play some part in my problem, but it causing a bigger drop in the Rad like Delmer explained makes more sense. When we were trying to flush the old Radiator, before we made the decision to replace it, we got a lot of sediment out, even run a laundry powder mix in it for a bit which removed a lot more than we got with just water. When we pulled the radiator out and seeing what was in the top and bottom tanks I was expecting something like you spoke of in the engine. When we looked in the side of the block (cooler bonnet piece removed) and under thermostat, the engine looked very clean. Cleanest part of the system. So I dont think I have the problem in the cylinder block and head like you said you have seen. I am really hoping i dont have to pull the engine apart to check inside... fingers crossed its something simple I have over looked like the baffles
Daft question. Is the fan spider installed the right way round.? Installed backwards it will still push air forwards through the radiator, just not as much as it should. Post a photo if you’re not sure.
Thanks Delmer Making the Rad hose temp diff bigger makes more sense due to keeping it in the Rad longer for sure. I was thinking if it stays in the engine longer it might pick up more heat a bit like a stuck thermostat and eventually add more heat than the system can get rid of? This is my crazy theory that I came up with when I ran out of more plausible options to chase... the more I think about it the less sense it make though. Missing baffles like Nige said sounds much more likely than my idea! The pulleys looked ok to me but I will get some pics and see what you think if you dont mind please. I thought they must have been buggered even though they looked ok till I put the Cat belts back on and they fit properly. The fan sounds like it is louder and has a different tone with the cat belts on and seems to be moving more air out the front now. Took a little longer to heat up as well. I dont think I am getting any slip but like you said a little bit of everything could be adding up to my problem. That way of unplugging the radiator cores with water and air sounds very good. I have kept the old core sections so I'll try it out when i get a chance. Anyway thanks again everyone I'll get to bed and report back tomorrow!!!
Ohhh good question Nige I dont know. I have seen it mentioned on here before but i forgot to ask about it. Ill get pics tomorrow and see what you think Thanks
When you post a pic of the spider be sure to indicate in which direction the fan rotates.
the important thing is was the transmission cooler and oil cooler completely stripped down with all the water tubes poked clear, the transmission cooler blocks from the bottom in some order, you can check the regulator for correct function with a heat gun or Flur off your phone, as you will see the temp drop as the reg' opens when targeting the top side of the spin on filter. tctractors
Yes when we did the Radiator they were both pulled off and inspected. The Trans cooler was completely clean in every tube and the engine oil cooler had a few tubes blocked but the majority of the rust was too big to fit down the tubes. It was packed loosely up against the tubes on the in side. I have had the engine oil cooler off again to check last year. There was a couple flakes of rust that must have been still in there somewhere and missed in the clean up but clean otherwise. I check the temps again today and the regulator looks to be working correctly so I didn't pull it out. I had a regulator but no new gasket so didn't want to chance it if it wasn't needed. I will pull it out if you guys think it needs to come out. I have pictures and more new info to put up so I'll post it now. If i can work out how to get pics up here off my phone!
The fan forgot to double check but I am sure it goes anti clockwise looking at it from the engine side so blades rotate down in these pictures
The restrictor in the thermostat housing pipe
The part no and writing on the outlet.
Looking through Radiator and pics of the pulleys. One of the pulley pics I didn’t do a good job of rubbing the dirt off for the pic sorry.
Top and bottom baffles were missing so I made up some makeshift ones out of plastic sheet and the temps seemed to hold steady around 100-103*C working rather than running away and cooled off a lot quicker when I pulled up at high idle. So it made a big difference! I couldn’t find where the side baffles were supposed to mount but I might be able to poke them in the sides and it might make it better again?
Still not a big enough temp drop is it? Seems to be now about 6.5-7*C Ambient air temp was a bit cooler today, supposed to be 39*C
According to the Parts Manual for your S/N #4 is a 100-4852 Pipe. The 8N-0743 Orificed Pipe you have installed right now came off a D7H if it came from a tractor, or a 966D/E/F if it came from a wheel loader as suggested by TCT. I suggest that you get the correct part installed ASAP and see what that does. Then the fan spider is installed in the correct orientation.
This guy shows how to measure wear in pulleys, you can skip to 2:30, and you don't need a gauge to see the wear. You don't have a rounded bottom like his three groove completely worn out pulley. You're looking for a straight edge of the V on both sides. Those don't look bad, but I'm guessing I can't tell much by the picture.
Make sure you get that rubber around the fan shroud up tight to the fan or you will lose a lot of fan efficiency. I see by your core pictures this machine has an oil cooler in place of one of the engine rad cores. I know one guy here has been removing that oil cooler and adding an extra rad core because he was always having problems with high temps on all the D6H tractors. He then added a separate oil cooler core in front of the rad. It seemed to solve the problem. Just something to think about if you can’t get it solved.
Thanks Nige. Just checked availability through Cat. This seems a bit extreme considering what the part is!!! None in Australia either, has to come from USA. Waiting to here back from a aftermarket/secondhand supplier to see what’s available.
Thanks Delmer Very good video, I’ll check mine again and make sure
Thanks Mobiltech I’ll see if I can get hold of a new rubber piece for the shroud. My gap is a bit over spec I think and a couple holes, I had a really good look at it yesterday… cant be helping. I don’t think they are very expensive either. That idea for the extra rad core would make a big difference. When I read you post I realised that is the difference between my 966G loader and the dozer. It has an external cooler and seems to work a lot better on the hot days. It is more horse power too but dozer might be a marginal system at best? It sounds like the D6h’s have a reputation for running too hot do they?
Why wouldn't you take a grinder and make the hole bigger in your regulator cover ? Bad Bob
Yeah we opened it up with oxy set and die grinder on my friends dozer. Oxy and cast iron didn’t mix real well, but it did the job! I thought it would be a cheap readily available part but apparently not. I might have to just enlarge the one I have…. Can easy block it back up if it makes the problem worse.
Update: Still hadn’t heard anything about parts. So we pulled the regulator housing off and dieground it out to full diameter. From about 30mm to 50mm. Seemed to take longer to heat up and cool off a bit quicker when stopped. Temps still hovering around 100*C or just over. About a 6*C drop from top to bottom hose when reading 100*C on the gauge and 97.5 on the top hose. Also made some side baffles for the rad because I could still feel hot air around the back of the Rad near the fan, that fixed that. It made a small improvement. The day was around 40*C or just over and felt a bit humid so I’d say a bit of improvement in performance but still not what I would call ideal. I need to repair a bit of the rubber on the fan shroud (4in piece missing) but other than that I am scratching my head again. It is loosing some air there I know, but I was hoping we might have got more temp drop over the Rad up till now. Will check the Rad core temps for blockages internally when I get back up there but I am sure I did that the other day. Any wisdom or ideas very welcome!!!
Curious if there is a way to test/verify the cooling system is holding pressure? I’m not familiar with the D6H setup; but I suspect it has to build/create some (probably low like 5-6psi)?? My understanding is with no pressure you are going to get higher temps. Never mentioned- but no leaks, or required “tops-offs” needed with the antifreeze/water? I will admit that belt track furthest in on the pulley does look like the V is quite worn, but I don’t think that’s “the” issue (and tough to tell 100% from pic). When you had radiator out, did you happen to check if there was/is any scale/build up on the lower line/hose going to water pump? Seems highly unlikely, but you’ve checked so much I’m surprised you’re not seeing an improvement. While your fan appears in correct orientation, does it have all its blades?? Have you tried running the machine with one side panel off to see if more airflow would help? Or on the flip side, are any vents covered over that would restrict airflow?? also post up a pic of the whole machine (please), I’d like to see the rake it’s pushing around!! Wish I had the silver bullet, but keep after it, you will figure it, or modify it to make it right!! ; )
JAJ, did your regulator look like the 1 in the post No 29 by Nige, or better still put up the part number of the thing you fitted, i notice you love a good amount of pig jollop around a gasket face, you might need to have schooling on it's use, that crap only needs a smear to be used, you seem to have plenty spare, if you look on the top of the old regulator it will state a temp standard. tctractors
Hi D5Dan thanks for the post and thanks very much for the encouragement. Sorry for the slow response, that saying “Burning the candle at both ends” doesn’t really cover it… more like the whole bloody candle is on fire at once here lately! Haha some good suggestions!! The radiator cap was one of the first things I changed back when I first got the dozer, but that was a long time ago now and could need doing again! I’ll order one and put it on and see. It seems to hold pressure but I haven’t actually tested with a gauge. We are going back up today so I’ll see where we can connect a gauge. No leaks and doesn’t need any top offs everyday or anything like that. Occasionally it might be a little down but it doesn’t spew out the overflow when it’s hot. Sometimes when it’s been hot it might sweat at the overflow enough for dust to stick around the overflow. I thought this was pretty normal considering the temps. The pulleys do have a bit of wear but I don’t that’s the drama either. I have seen a lot worse still doing the job….. but I am happy to be told I am wrong on that too. No I’m sure I had the bottom hose off the water pump to flush it and it all looked good. Yep all the fan is there. I’ll try to remove the sides panels to check for any improvement. I had tried it before when I still had other problems but not this time. I actually found an old thread where “Scrub Puller” had said about having issues with the hot air from the radiator hitting the back of the Stickrakes and recirculating too. They made deflectors to push it upwards. I’ll post a pic of the machine for you and see what you think.
Hi TCTractors Yeah I couldn’t believe how much gasket goo I put on there when I pulled it apart!! I had to reuse the old gasket, that was the only reason it was on there at all and I was worried about it leaking. I don’t use any on new gaskets at all. I had to do the same when I had it apart to bore the hole out, but put a lot less on for round 2. Very well spotted. The regulator is a bit different to the parts diagram, Cat tells me this is the new part that replaced the old one, so I hope that’s right. I have the spare one in the car I’ll go take some pics, they are both the same. I’m sure they have 175 on them, there is a higher temp one available but these are the low temp option.
A pic of the machine and looking forward and backward down the cleared line to show what work its doing
What's the regulator Part Number.? I don't know what anyone else thinks but in your climatic conditions I'd go for the regulator option for the higher temperature.
Reg part no: 111-8010
Hi Nige just uploaded pic and part no of the Reg I thought the lower temp one would be better in hotter temps? I think it is supposed to be full open at 91*C if I recall the specs… I thought full flow at lower temps would mean it would run cooler over all. I could be very wrong though and very glad to be corrected!!!!!! I think the hotter option was full open at 97*C but can’t remember for sure. Could you explain what you think the difference would be between the two options? Thanks
What did the jiggle valve look like beside the regulator. Was there one in it? You should probably replace it too.
The 111-8010 starts to open at 79.5*C and is fully open by 91*C. The other option is a 116-7577 that starts to open at 86*C and is fully open by 97*C. Here's how I would explain it. I hope it makes sense. Everything else being equal the reduction in the temperature of the coolant as it flows through the radiator depends basically on two factors. How fast it flows through the cores from top to bottom, and the temperature difference between the coolant and that of the ambient air that is being blown over the radiator by the fan. So provided that the coolant is not overheated the temperature gradient between a hotter coolant and the prevailing ambient temperature obtained by using a regulator with a higher temperature would actually aid cooling. An interesting factoid is that the 111-8010 regulator is the one specified for use with the 8N-0743 Orificed Outlet Pipe which seems to back up the use of that pipe on machines working in colder climates. I think it's important to stress a few things in your particular operating environment: - 1. A lot depends on the coolant flow being as it should be right through the system. You said earlier you'd been into the water pump but what did you find.? Got any photos.? 2. The fan spider, pulleys, tensioner mechanism, and belts all have to be in tip-top shape. Were those photos you posted on Page 2 of the "will fit" belts that were installed previously or of the OEM Cat ones that are installed now.? 3. Air passing from the fan through the radiator has to have nowhere else to go other than through the cores. The sealing of the baffles on the fan shroud around the spider and between the shroud and the radiator have to be as perfect as you can get it. 4. You need good coolant in the system. I would recommend either ELI or ELC whichever you can get hold of, but ELI would be my preference.
You said that you had replaced the pressure cap on the cooling system. Do you have a Part Number.?
I respectfully disagree on the thermostat or regulator. The conventional thinking is the cooler temperature rating will give you more time from the thermostat opening until it overheats, in this case of hard work and high ambient temps, I don't think an extra minute or two is going to make any noticeable difference one way or the other, you're operating fully open nearly 100% of the time. We're past the common issues (besides air flow bypassing which might need some work yet). It seems there are parts there that didn't come with it, is it possible there are different size crank or fan pulleys that would change the ratio? or different fans? After that, maybe time to look at the engine itself, timing, spray pattern, turbo performance etc. All that is over my pay grade though.
I'd like to see better photos of all the pulleys, from the crankshaft upwards. Also some photos showing how close to the bottom of the grooves on each pulley the belts are running . It's the part about keeping the coolant temperature as high as it'll go without boiling that's the most important. I can't post the whole document here because it's too big, but I extracted this quote from REHS1063 entitled "Know your Cooling System". The amount of heat transfer in the radiator from the coolant to the air is directly related to the difference between coolant and air temperature. An increase in this temperature differential will increase the heat transfer. Normally, the design of a cooling system will permit operation at a temperature that is high enough for a good heat transfer, but low enough to prevent coolant boiling. I think the critical part in regards this particular tractor is the operation in ambient temperatures above 40*C, to me that suggests the coolant temperature should be kept as high as possible to maximize the heat transfer in the radiator.
Normally, the design of a cooling system will permit operation at a temperature that is high enough for a good heat transfer ... i don't think that implies a NEED to keep the temp up for good heat transfer, the temp rises to the point where it can transfer enough heat to maintain that temp. A cooling system that can maintain 160F won't have more capacity with a 190F thermostat than it would with a 160F thermostat but operating hard enough to run at 190. "Know your cooling system" comes up in a search as SEBD0518-09 and has similar but not identical language. "PERMIT" operation is the key, if 205F is what the engine runs at in those temps, that's fine, the engine doesn't care if the iron is 200, or 250 or 300. Trouble is when the coolant boils and localized overheating happens. That's why air cooled can run much hotter temps, the air doesn't boil, and the metal is thick enough to prevent hot spots as long as the air is moving. A few suggestions from the publication: photo tach for fan speed, if you know the fan speed spec, a cheap photo tachometer can tell if it's slipping. It mentions more than once not to operate near torque converter stall speed, I interpret that as keep the engine well ABOVE torque converter stall speed for most operation, that is, at rated engine speed or close to it, even without a torque converter.
G’day JAJ, Difficult to tell in your pic but it looks like you have the rad. guard with angled slats which should be enough to send the hot air upwards and out of the way. The size of your rake, timber etc. should be easy going for a D6H. Are you pulling an implement at times or just using the gps to map out lines?
Hi sorry for another delay in getting back to everyone. and for the long post There is a few posts to answer so I will get to that in moment, bit of an update first. I worked the machine for a few hours yesterday to actually give it a good test to see how the improvements we have worked out so far are helping up to now and test with a door off as well. I couldn't hook a gauge up to test Radiator pressure with what I had with me but with everything up to temp, if you lift the valve on the rad cap it seemed to have quite a bit of pressure in there. So I'd say it would be working correctly. It has 50 stamped on the top so I expect that to be 50 Kpa (7.25psi). It is a genine Cat one and it looks like the one Cat lists on the website for it, I can find the old invoice and check part no. if you want? So temp comes up rather quickly to 80*C then slowly rises to 91. It pauses around there for a while then slowly rose up to 98-100 and stayed there for a while but slowly crept up as the day got hotter. Around lunch time it was up around 104*C. I pulled one of the side doors off for awhile at this stage but it made no difference. I did notice at this stage too that the AC condenser was getting plugged up again (only done a few hours since last cleanout) so we blew that and the whole radiator out and air filter. Lots of dust came out of the rad core. I do an initial clean then repeat with engine at high idle to get extra out (best way I have came up with so far for field clean out) After doing this I expected that there would be even a small drop in temp... absolutely no change, it ran at 104*C for the rest of the afternoon. It was a 43* ambient temp afternoon so rather hot, but a cleaner radiator made no difference to the coolant temp!! More air through a cleaner radiator has to mean more heat out... if that was the problem wouldnt it? This is the key point that has had me stumped all along, and I blew it out mid way thought the day to make sure I wasn't just convincing my self that it was happening, about as scientific as I could come up with. Any other machine I have the moment the coolant temps rises above its normal range it signals time for a clean out and everthing goes back to normal. I also double checked temps of the core sections and the temp drops from top to bottom were the same on all cores at the end of the afternoon. It was extremely hard to get accurate temps with the amount of hot air that was blasting out the front with it at mid Revs, what i imagine being in a fan forced oven feels like. I was thinking afterwards maybe I should have checked this as soon as the temp got to something like 93* so it hadnt had a chance to soaked though the Rad if things were blocked but I haven't convinced myself that it would make much difference. Happy to repeat if you guys think that would be better? I forgot to take the tacho up yesterday to check fan speed as has been suggested but I am going back tomorrow because I want to take the muffler off to make sure an exhaust restriction isn't a contributing factor. This is something I realized I haven't checked yet and I wanted to rule it out. That "Know your cooling system" is a very good read I have it saved on my phone for reference, there is also a dozer specific one as well that is an extra add on that I found a while ago. It added a few other things and I thought was worth reading too. So up till this point of the thread I have tried to just state the facts as I see them and not bias them with my own opinions to much (hope everyone thinks I have done a good job of this). I didnt start the thread to find people to validate my ideas, I wanted to share the facts with some other like minded problem solvers and hopefully brainstorm a solution... and all of us(especially ME!!!!) learn a bit in the process. SO with that said I an going to give my interpretation of the facts and see what you guys think. I welcome to be corrected or challenged with anything I say, I am here to learn and are very grateful for what info and knowledge everyone has shared so far!!!! Here is my take on what I see happening. The thermostat/regulator is matching up with pauses at the correct temps as per the specs so I think this should rule it out for misbehaving. I hear what Nige is getting at with higher coolant temp meaning better heat transfer but once you get to 97*C both regulators are going to be fully open and at max flow. This should mean that at that point the system would function the same regardless wouldn't it? As I understand it if heat keeps getting added after this then you get to a point where it should balance out at the systems capacity to shed the heat. I think this is what I am seeing when it levels off at around 100*C and the rises as the ambient temp goes up. Please set me straight if I have this wrong, but I think that is the theory isn't it? A coolant temp of over 100*C is too hot isnt it? I just want to make sure that we all agree on that. Just thinking about it and if its not boiling and spewing coolant out is it really too hot? I am worried it is over 95*C but with high ambient temps what should I be aiming for? The manual suggests normal operating temp range is 75-93*C and the warning light should come on at 107*C. Ok so if it is too hot, where is the heat coming from and why isn't it getting rid of it... the fact that I did the test with blowing the radiator out has me directed back at excess heating rather than not enough cooling. Just my thinking trail.... I could be and probably am incorrect. The torque converter/trans temp (once everything heats up) is 5*C hotter than the coolant. It heats up a bit more if you load the machine right up and travel speed slows right down but cools off back to the 5* when the load is lessened. I don't let it slow down very much from rated speed with a load, once you notice and feel a slight difference in speed it's time to get rid of the pile and start again. So I am thinking thats an unlikely cause. That has me looking back at the engine. I know the intake isnt sucking hot gasses back trough the dust ejector, but I dont know if the muffler might have a restriction. I think this could cause heating and it is about the last easy thing I can think of to check. I figure if I put a straight pipe on it and it makes no difference that is ruled out (going to try that tomorrow). I'm not saying that the pulleys and belts are not still a possible factor but I am thinking unlikely. The pics I took were of the used Cat belts that I put back on, the new ones that I have coming still havent showed up yet. Have to chase them up. The old belts were sitting right down in the Vee's but these seem to be up ok. The fan shroud is a small factor I believe for sure but I really think there is something else that is the more major cause. If its not the exhaust I really hope I am wrong!!!!! I did have a overheating issue on a small Fiat dozer (first one I got) when I had the injector pump rebuilt. I got the timing a little out when i re installed it and it was lacking in power and overheated very quickly. So that is something I had wondered about but haven't checked yet. Flushing the Coolant out where the machine is would be a challenge. I am looking forward to doing it and getting ELC or ELI in there but getting enough clean water to it where it is, is going to be hard. I have talked to the client and we can wait till the days cool off a bit to work it back to a source of rainwater if we need to as an option. When I do it I was thinking some cooling system restorer might be worth running through it as well? Might pick up some more efficiency in the radiator? The water pump impeller (cast not plastic) looked good and clean when I had the cover off but I didnt take any pics. Do you think with the evidence we have it could still be a suspect? Anyway looking forward to reading everyone's feedback on my theory's in the morning. I will get the fan and engine speeds tomorrow hopefully and test the exhaust idea. I think so far we have made a big improvement with the fact temps aren't continuing to climb and are actually now stopping. So we are winning bit by bit. Bloody late here now so well past my bed time.
G'day to you too! No mine has the flat guard with holes in it not the angled slats. Just using the gps for mapping lines so far but I had wondered about trying to rig up some type of auto steer. Makes keeping straight a lot easy than handheld GPS and back siting ect. I like being precise and it looks good to see a new fence or cleared line being dead straight for kilometers. The line we are on at the moment is over 10km I think and its nice to come out exactly where you are supposed to!
On my Caterpillar 328DLCR, simply air blowing the radiator became not enough. Soap and steam were required, even though I could see clearly through there. It was a dust coating that originated in one region of WV. The telltale signs were that air filters wouldn't blow clean after 400 hours, and the small temp drop across (technically down) the radiator, even with the electro viscous fan on full time.
I have the latest version of the dozer one if you want it, but it’s too large to post here. Check your messages. Interestingly it has details of a High Ambient temperature radiator core Part Number to replace the one listed in your Parts Manual which IIRC is 4P-something.
I find this thread fascinating . . . you guys are working when its 109.5*F out? Up here in northern Wisconsin it hits 95*F and the men start passing out, the machines overheat, the trucks catch fire . . .
I had cooling issues with my D6c , wasn’t overheating but temperature gauge was running up close to the red marking. I took it to Ziegler caterpillar,they found the problem was rust buildup on the bottom of the radiator,also they put new water pump on which didn’t look bad but water was escaping the impeller. I put new radiator on with the water pump and it has been working fine for me. Just my two cents worth.
Try the Indian sub-continent or the Sandbox (Middle East)....... I've experienced temperatures around 40*C @ 6:00am in Northern India and high-40s as a max. By law in the ME all outside work has to stop when the mercury passes 50*C (122*F). Amazingly there are lots of days when the "official recorded max" is/was 49.5. Go figure.
It will be interesting to see how the new belts sit on both the crank and the fan pulleys compared to the ones that are on there now. I know it's hidden down in the belly of the beast but the crank pulley also requires to be carefully inspected for wear. Unfortunately the photos you posted on the previous page didn't clearly show how far proud the belts sat above the flanges of the pulley. As you mentioned above, all may well be revealed when you are able to measure the fan speed with a phototach.
My first reaction, what was the temp drop across the radiator, or the outlet near the thermostat to the water pump inlet? and are you reading the block temp directly? or the dash gauge? I'd expect even with a mostly plugged radiator, or a fan on wrong, or some other serious issue, that if you can work for hours without losing coolant then idling at medium speed for five or ten minutes should drop the temp back very close to the opening temp of the thermostat. The fact that it doesn't drop back, and the very slow temp climb, makes me suspect the gauge. Otherwise everything else you say makes sense. "Normally, the design of a cooling system will permit operation at a temperature that is high enough for a good heat transfer," That is an admission that cooling systems will operate in marginal conditions, in my opinion. It's marginal to operate bumping against the overheat warning, but not harmful without overheating (losing coolant or boiling in the system). I would feel much more comfortable with the highest pressure cap recommended, 15# instead of 7# would add about 20*F to the boiling point.
Sounds like you need to put on your auxiliary cooler full blast. It is a cab operated switch that gets turned into the red zone that may increase operator discomfort when active lol.
So the fan hub on a new truck cuts in at about 102c or 215 f. They way I see it is if the temp stabilizes at 104c in 40 c weather and it isn’t boiling coolant out carry on with your work because you really don’t have a problem. Just make sure you have the high ambient cooling package. cat used to say on the D8n that seemed to always run hot if the light isn’t on you haven’t got an issue. If it was 40 degrees here we would expect to see many machines running over 100c. I melt in anything over 35c. That weather is only good for being at the lake.
HAHAHA Yeah i would have already tried that.... but my tractor doesnt have the "Auxiliary Cooler/Operator roaster" package on it. Have seen it work on cars before though!!!
Hi I am a bit short on time this morning have to get ready for some goat mustering here at home, so will answer everyone latter today when the pressure is off a bit. Thought I would put up the results of the tests yesterday for people to analyze. So pulled exhaust off, my straight pipe was a bit short and I was getting some gas staying inside the engine area. It seemed to run a little cooler and cool off faster. Ambient temp about 40*C or just under Coolant temp was working around 100*C by the time I would get out and get the engine door open to use the temp gun it would read Top hose: 92.9*C Thermostat housing: 92.4*C Bottom Hose: 88.3*C Quickly checking the gauge in the cab it was back to about 95*C It was later in the afternoon when I did this so the ambient temp would have cooled off a bit by that stage. Id expect just under 40* Fan speed test engine just started cool. Engine low idle: 654.7 Rpm Fan: 423 Rpm Engine High Idle: 2174.5 Rpm Fan: 1319.9 Rpm Fan speed test with engine hot just before we stopped for the day. Engine low idle: 649.6 Rpm Fan: 393.5 Rpm Engine High idle: 2170.3 Rpm Fan: 1312.2 Rpm We also did a Torque converter stall test just before we shut it off for the afternoon. 3rd gear full revs stalled with brakes: 1653.5 Rpm. I had a quick look for the engine and fan speed specs but couldn't find them. Will try again later to find them. The percentage of reduction from engine to fan was the almost identical at both ends of the rev range (0.01%) and with everything hot it was about the same so that is pretty good I think, what does everyone else think? The stall test rpm seemed a bit low to me but I cant find the spec for it either yet. What does everyone else think here as well? Looking forward to hear what you think of the results.
Converter stall speed with everything at operating temperaure should be in the range of 1600-1650 RPM IIRC. Did you happen to take a look inside the original exhaust pipe.? What was the condition of the venturi, especially the nozzle, for the dust ejector system.? I don't suppose you tested to check how much suction there was on the dust ejector hose connection with the converter stalled did you.?
Hey Nige Part way through doing an engine service on the aeroplane, came back into wifi rage to get oil and a filter and thought I’d check to see if anyone had answered. Sorry I haven’t got back to your PM yet. Yep didn’t realise there was a Venturi in there till I pulled it off. Engine side of it is rusted off. I’ll post a couple of pics later on. The nozzle bit in the muffler looked good but the rest of the muffler has some rust issues so I was thinking is could very well be rusted on the inside causing a restriction. Thought I might cut it open to see for sure. no I already had the muffler off when we did the stall test. At high idle no load there was suction though.
Bottom engine side of the Venturi Had a good look inside the muffler box with a motorbike mirror out in the sun… inlet side looks ok…. Outlet side is mostly blocked up with rust. Couldn’t get a good pic of it. Will have to get a new one and top piece. I might get a new precleaner piece while I’m at it. Unless you can get the plastic tubes separately?
Not wanting to drag up the Regulator again but I seem to recall (I think that is??) the regulator you posted in the picture has a seal that locates in the C/head that catches the bottom of it, the lower seal is important to the cooling flow Nige could check this point ? tctractors
You mean a lip-type seal Tony.? Not according to the Parts Manual. #1 is the regulator, #2 the gasket, & #6 the jiggle valve. I also looked in the cylinder head just in case but not there either, not that I was expecting it to be.
The Regulator that has been fitted 111-8010 I think is the type to have the lower Lip Type Seal fitted and is not the same Regulator type as in this parts shot??? tctractors
So here is what I've found. The temperature regulator in the illustration (machines 4GG5500-Up) is a 7E-3362 (formerly 7N-0208). According to SEPD0043 dated 29/10/1990 - "The new 7E-3361 and 7E-3362 Regulators are direct replacements for the former 7N-0208 Temperature Regulator (cancelled) depending on the application." Then we have SEPD0289 dated 22/01/1996 - "A new water temperature regulator is available for 3304 and 3306 Machine Engines. This new water temperature regulator has a low leakage rate and eliminates pressure pulses in the cooling system. The new 111-8010 Water Temperature Regulator replaces the former 7E-3361, 7E-3362 and 9Y-4000 Water Temperature Regulators. See chart for adaptability." Neither of those articles makes any mention of an additional seal, or of any cylinder head rework procedure necessary to use the new Part Number of regulator. I know the type of seal you're referring to, all the 3500 engine temperature regulator housings use them. Now the OP's tractor S/N 4GG05795 was built on 25/03/1996. So according to those dates it should have been built using the 111-8010 regulator. Using the machine S/N the regulator group is a 100-4851. The regulator changed from 7E-3362 to 111-8010 in that Group on 15/06/1994, 21 months before the OP's machine was built. If I can throw a curve ball in at this point. We already now that the outlet pipe was incorrect for the application in this machine, having originally been fitted to a D7H (also with a 3306 engine) if it came from another tractor. Going back to what the OP said a while ago - "Dug up history on it since and engine and TC only have about 4500Hrs I think if I remember right. Engine done by Cat dealer and Torque Converter was exchanged reman." So I wonder if at some point this tractor has had a cylinder head replacement using one that was configured for another machine model.? That could explain a lot. To muddy the waters even more, below an illustration of a 111-8010 as installed in a (much later) D6R engine, long after the 7E-3362 regulator was discontinued but still no sign of a lip seal.
There was no lip seal in there and I haven’t seen any on the parts diagrams for this engine or the engine in my 966G wheel loader (3306 as well). I had trouble when I got it with the transmission overheating as well and heating the engine up a bit. Pulled the thermostat out to check it and was very surprised how it worked. When I saw it I was expecting a seal something like TCTractors was thinking but apparently the 3306 doesn’t need it? Seals steel on steel. Nige has uncover the very interesting history of it all by the looks.
JAJ, the seal fits into the head and acts on the bottom section of the regulator in lots of 3306 DI engines, it forms a tight grip on the lower reduced width section of the regulator, the bit with the line and 1 on the end with the seal fitting in the bit of head below, Nige has pulled out all the info on this point to the highest standard and I thank him, I wonder what other mods are done to the engine to complete a Cold Climate spec', the effort you have put into trying to cure a what should be a simple overheat problem is commendable, it's got to be something simple. tctractors
It might be interesting to get a Part Number from the cylinder head that is currently installed on the tractor..? If it's not the one that's supposed to be on there according to the Parts Manual then the possibility exists that, as TCT points out, there ought to be a lip seal on the bottom side of the temperature regulator for that particular Part Number of cylinder head . It won't be in the Parts Manual for the tractor because the Cyl Head Gp isn't isupposed to be fitted to it. It may also be the case that the regulator Part Number is incorrect for the Cyl Head Gp in which it's installed. I'm just wondering if the solution might prove to be a combination of more than one small incremental improvements that, when added together, improve the cooling system efficiency sufficently to solve the problem.
For what it’s worth in all the 3306 heads I’ve done and thermostats changed I have never seen one with the lip seal like a 3406 uses in our part of the country Jiggle valve yes seal no.
Next thing would be to measure the temp of the oil lines going to the transmission cooler on the side of the engine (Water Cooled) and the oil lines on the air blown transmission cooler to check the regulator is working o.k. between them. tctractors
I forgot to ask about this when it was said earlier in the thread. Mine only has the water cooled transmission cooler and I haven’t found the regulator valve that you speak of. I read about it somewhere on the internet back when I first started pulling the cooling system apart. I can’t find it in the parts diagrams for my machine but I do think that I found it in the parts section for a different prefix d6h at some point. I was attempting self education and studying different prefix parts manuals and service docs on SiS incase the manuals for my machine (Japanese built LGP) didn’t have all the updates of the USA manuals. I can’t remember where I found it or under what prefix though. Someone might be able to direct us in a direction or I will see if I can’t find it again? I will also see if I have temps of the trans cooler from recently too. thanks for bringing this back up so I can ask these questions!!!!
Bit of a general update too…. I have ordered the parts for the exhaust and dust ejector, also the pre-cleaner bit. I was talking to Nige about maybe going to a Syclone pre cleaner but thought I’d just put everything back as it was so I don’t have any dramas getting wrong bits and more delays. There is some interesting service bulletins for the pre cleaner stuff from Syclone even giving part numbers for changing over if anyone hasn’t seen them. They are supposed to be better than the system I have but has anyone swapped over to them and what do you think? Also the rubber fan shroud bits are coming too but 3 of the 4 have to come from overseas so they will be a bit of a wait. The parts will take a week or so to get to the nearest Caterpillar outpost then we have to go for a trip to get them. So while we are waiting I have moved on to another job with the wheel loader to keep the bank balance going ok. Might be two weeks before I get back to the dozer now. Getting a part no for the head will be very interesting. If it has been swapped it could explain a bit for sure! I would also like to know what else is part of a cold climate kit (if it’s a thing)… the missing valve that TCTractors is talking about could be part of it??
hello from europe, folowing your problem as overheating is something that afects as all every now and then... i have a d5h , lots of problems but overheating was not one of those... the other day i broke the exaust elbow that goes from turbo into the silencer... as like u in the between fixing i continue to run the machine... then bum overheating problems started... haven´t adressed those yet cause i´m pretty sure that they are caused by the exaust being some how being pulled throug the rad... funny hein... From other experiences i´ve had, when cooling system can´t deal with the heat usually its related to core of cooling system, as someone mentioned here u got to have significant temp drop across the top and botom. u´ve reported rust inside system , i bet my 50 cents that rad is clogged... the clues are all there , machine overheats and do not behave naturaly, 2 min at idle its all it is needed to cool down if problem is caused by trans oil or engine oil heat build.
I am fairly sure you would have an air cooled transmission cooler and a water heat exchanger on your tractor, the regulator controls the oil flow to both of them, it would not show the regulator in the cooling system, try looking at the oil lines from the converter outlet. tctractors
According to what's shown in the Parts Manual for 4GG5795 the power train oil cooler is the oil/water type, the same as the engine oil cooler.
This is the parts diagram off SiS for my machine for the oil lines to the cooler(heat exchanger). The oil lines go from the converter outlet relief valve to the watercooler then back to the transmission case. That’s how I remember the lines are set up on my tractor as well. I’ll see if I can find it on another prefix.
You beat me Nige!! When I hit the post reply and it reloaded the page you post popped up.
I don't have a parts book for a 4GG only a 4LG, so best bet is to open the engine side door r/hand from the seat and look for oil lines going to the radiator, then get the cylinder head part number to check the correct regulator.
We're still looking at a low temperature drop through the radiator for the coolant. That suggests the coolant circulation is fine, and the air side is the issue. I'm hoping the fan baffles makes a big difference in the temperature numbers. If not, I'd like to see if the pulleys and fan are appropriate for the high ambient temps, or if there are better ones available.
If the temperature drop through the radiator is low (4*C IIRC) couldn't that possibly suggest restricted flow through the radiator.? I would have though the slower the fluid moves from top to bottom the closer the temperatures would be between the top hose and the bottom one. I know the OP said he found lots of crud in the top & bottom tanks when he stripped down the radiator some time back, and at the same time he installed all new cores. I wonder if the crud he found was also present elsewhere in the engine (e.g. around the liners and in the coolant passages of the cyl head) and that crud has now dislodged itself.? If it has then my favourite of a potential place for it to land would be the coolant passages in the radiator cores. I checked. Nothing official, which is not to say that something designed to fit another model might not work. Finding it would be the challenge though.
I am struggling to understand a few things here, it seems the rad might be new or blocked, the coolers might be clean or dirty, the engine or at least the head might be off anything but a D6H-11, the temp regulator looks so wrong to me that its bothersome, the thought that I have in my mind about Transmission cooler fan blown would be fitted, the common head fitted to the -11's that I recall was 8N6796, the regulator would be 7E3361, I took a head off a -11 in late 2021- early 22 with a load of broken bolts in, the photos of this is where I have the part numbers from, to test a cooling fault on a high drive I always check all components in the system and leave the guessing to other people, if I could not effect a satisfactory result I would rip the head off and possibly whip out the liners and start from fresh. tctractors
Hi all got up to this loader job and we can use the wifi here so have internet. Ok Nige, TCTractors and Delmer do you guys think that in 40+*c (105*f) ambient temps that Coolant temps should be better than 100*c (212*f)??? I thought the general consensus the other day was that newer stuff runs over 100*c and now that it’s stable at that, although it is warmer than we would like, not to worry too much. Especially since when you stop now it drops back faster too? Don’t get me wrong any improvement on this temp I believe would be a wonderful thing and I’m all for chasing it!! The temp drop over the rad has me puzzled too. So as I understand it if the core were blocked slowing the flow that would be indicated by an abnormally large drop from top to bottom hose. A low flow due to water pump would do this as well I think ie. any low flow in the system. Now it was suggested by a mate that I have (that loves chasing problems like this too), that if you have blocked sections and free flowing sections due to the design of the radiator that you could still get a low drop because all the coolant flow is being sucked through say three sections and that the rest of the rad would be just sitting still. This is where I thought I could rule that out with checking for hot and cold spots over the cores and they seemed to all be the same drop top to bottom. Let me know if you don’t agree with my thinking and if I’m missing something please . I don’t think there is a massive airflow drama but a small one could be contributing for sure. I did read a thread somewhere that the bloke swapped pulleys from a different tractor d6h - d6r or the other way around can’t remember, to speed the fan up. A steam clean of the radiator would be good as well in case the little bit of dust still in there is insulating it as well. That’s just bit hard where it is until we work it closer to a water source. My thoughts are now directed to why the coolant can’t get rid of the heat again. 1: Is the coolant not good enough to do the job? 2: is there some kind of insulating film in the radiator that I can’t see that is stoping it from transferring the heat out of the coolant? 3: if there is a film, when I swap the coolant would a cooling system restorer flush eliminate this? Of course this is all on hold testing wise till I get the new exhaust and eliminate that and see where that leaves me.
1: if the coolant is relatively new and no more than 50% coolant, it shouldn't be a factor. I stated that water has better heat capacity and lower viscosity than glycol, but it's not as great a difference as I had thought, and the higher boiling point of the glycol could easily offset the lower specific heat capacity, especially in high ambient temps. 2: Yes, Nige has mentioned on other threads that bigger radiators like this can have enough film to slow heat transfer but not enough build up to block the flow, so that the deposits will reduce the temperature drop just like a dirty outside or low air flow will. I've never seen that, mostly because blocked radiators I've seen are mostly smaller than this, are blocked with lime scale that blocks the top of the tubes, and almost never do anything in 40C. 3: I'd guess running it with rainwater once or twice to confirm there's no sediment, then a flush chemical would be plenty. The cores are all new and it had new coolant at that time, but previous rust. The most important thing to learn from draining the coolant and flushing is how much sediment comes out, back flush the radiator if you can't see the top of the tubes, check the oil cooler per TCT. JAJ, I agree with your thinking about the temp drop through the radiator. If the exhaust is leaking at all into the pusher fan, and the fan shroud is leaking, the high ambient temp is already your limiting factor, so that would be enough to make your cooling marginal. I think your operating temperatures are marginal, but as long as you're not losing coolant, and the cap holds enough pressure to keep the system above the boiling point, then it's safe. But you'd be more comfortable if the temp stuck exactly at the full open temp of the regulator, and if it climbed above that you knew you had to blow the dirt out of the radiator. If the coolant flow was reduced because of a worn impeller or a stuck closed regulator, then the temperature drop across the radiator would go way up. Just like if it was operating at -40, the regulator would barely crack open before the incoming -30 coolant mixed and reached the regulator to shut it closed again. If the coolant flow could be doubled from your existing operating conditions, then the temp drop would be roughly halved, even as the radiator would expel slightly more heat because the bottom of the radiator would be hotter therefore the air going through would be heated more. If there's only 4 degrees drop to start with, then doubling the coolant flow will raise the average radiator temp 2 degrees, so it won't dramatically increase the heat rejection quantity. 75C air to 100 vs 102 average coolant temp. so 27 instead of 25C temperature difference from coolant to air. If we guess the average air temp going into the radiator is 60C from heat off the engine, and the average air temp coming out of the radiator is 90C, then doubling the airflow would drop that 75 degree average air temp to 67.5, so a 32.5C difference between the coolant and air, vs 25 for original airflow, or 27 for original airflow and double coolant flow. You can see the airflow is critical the higher the incoming air temp. If you have a dial probe meat thermometer that reaches through the cores, that could measure the air temp before and after the radiator in a few places and figure out what we're working with. Obviously you won't double the airflow, but you might improve it a enough to make a difference. "I would have though the slower the fluid moves from top to bottom the closer the temperatures would be between the top hose and the bottom one." No, assuming the airflow is the same, the longer it takes the coolant to pass, the more it will cool off, approaching the air temp. That assumes the flow is even also. One side of the radiator blocked and one side open will dramatically reduce the temp drop and heat rejected. Blocked tubes spread evenly over the radiator won't make as much difference because the fins will transfer heat better to the blocked tubes and continue to reject heat from all the radiator surface.
Hi everyone sorry for the long delay, I’ve been meaning to post an update… we finally got back to the dozer about 2weeks ago and fitted all the new parts (exhaust, ejector, pre cleaner ect). I think the clogged exhaust was worth probably another 2*c. It has cooled off a lot now on the ambient temp front too, but after a couple hours working it was back up around 100*c on the gauge. When you pull up to check temps with an infrared gun it drops back very quickly and the gun reads about 92*c. I did a quick check of stalling the TC until it brings on the “idiot light” (red warning light on dash). I can’t remember exact spec without checking the manual, but I think it’s 130*C, anyway it reads 10*c hotter on the gauge than the spec! So I think I have an electrical issue causing a high reading on both gauges. I’m not sure if this has been getting slowly worse and has been hiding behind the other things and contributing all along or is a new issue. I’m leaning towards hiding in the background the whole time making everything look worse than it was. After this I also found if you switch the ignition key off for a few seconds and then back on, the gauge will read something like 5-7* lower instantly and then over a few seconds slowly rise back up to 98ish. Someone on the forum suggested that I could have a gauge issue but I had already replaced gauge, sender, and wire to sender and thought I had that covered. I think I have also run an extra ground wire from the alternator to the dash panel but can’t remember for sure. So I think there could be an issue with resistance on the positive side through somewhere. I’m thinking the ignition key switch, but I didn’t have time to test it. I needed to get the last of the job stage finished and I have now had to move on to a grader job building erosion control water ponds. I’m probably not going to get back to the dozer for a few weeks again now. Nige you were 100% right about setting the dust ejector up correctly too! I had to trim the joint to get the alignment correct. It wouldn’t suck much at all as it came from Caterpillar. That’s a big trap isn’t it!!!
Unless that dust ejector is sucking right the adverse effect on air inlet temperature is significant. It is a trap that’s true. Always reminds me of my Indian mate Bindair Dundat……..
We have a D5H of the same era at our farm... and is a nightmare of electrical problems... all u´re saying and a lot more... last one was the dash fuse started to blow... out of nowhere... red lights off at least... i guess is something inside the logic of this electronic box wich also show some lights... Our tractor also used to overheat, but between the engine, TXM , and cooling apparatus, a lot of things were contributing to it, the most evident was the exaust beeing broken was releasing a lot of hot gas throug the radiator... then we indentified lack of power and we found out the previous owner had reduced the fueling, tractor was overheating due to stalled TC . Next we´ll be doing, is clean both the radiator and the TXM cooler , i bet a 30year old machine will have the trans cooler needing cleaning or a maybe a new one, radiator can be seen very dirty. regards.
Yes the whole old tractor being neglected for quite a while is sure a drama that can be hard to unravel. When there is a problem with so many contributing factors it gets extremely frustrating as you tick them off and see only a small improvement, but hang in there you’ll get it sorted!!! I’ve learnt a lot as I have unraveled mine, so there has been a silver lining. Very interesting that you mentioned low fueling. I don’t think it is a problem with mine, but worth checking. I have a friend that is having overheating dramas as well and the mechanic that worked on it before he purchased it mentioned he turned the fuel down due to smoke and boost I think. I’ll tell him to check it. How did you check yours, boost pressure or the rack with a dial indicator? Best regards
Well, i was led to that conclusion due to a chain of events... nothing to do with overheating... but a sedden smoking folowed by low power... and this lead the tractor to overheat once and blow the coolant out, then u know its hot... Happened that the cause was an obstruction on the intake, the rubber seal between the hood and the filter housing managed to fold and obstruct the intake, machine started to loose power and overheating. This led to check´s on turbo, intake system, fuel system , engine compression , blow by , and so on, as there was no signs of a bad engine... then visual inspection on turbo revealed no reason not to beeing working correctly, measured boost and show maybe 5psi at full load, and that anybody know is too low, after carefull inspection no leaks were found, and the injector pump in that engine has no Altitude compensation, so the engine must smoke at least when u WOT from idle, as it should... Beeing familiar with injection systems, after some checking it was too evident that someone had been there, doing what i don´t know, increased the fueling 2 turns and "voila" boost came to 10 psi wich is still low but enough for my job at the moment, and the black smoke when one WOT from idle. In the future i have to find out the CAT paper with the numbers for the right boost nr and the right dynamic timing. (something wich nobody here really know about, it seems like a TOP Secret matter...) To your question, and based on my experience with injection pumps... the rack measuring procedure is not suitable for this type of job...(in bench test yes) as the rack might be in the right place but the TQ compensation might be off and then there is no way i figure it out... but one still have 2 procedures that might be used to determine right fueling.... along with other signs... 1-measuring the output phisically of one injector with the engine at full load, wich is quite dificult, or engine disabled rack at full THR and measure injection amount in one minute, but for that u need comparison... or the CAT field paper. 2-watching boost and smoke, and trying out the machine, the boost nr for that engine is on CAT field checks too, usually increasing fuel until one hits the desired boost might be tricky, as one must always check it at full load and watch the smoke... if it turns out too thick one must consider place altitude. Not wanting to lecture anyone, dealing with the injector pump might be treatchuress.
Thanks Mquinista, sorry for my slow reply. I haven't done any adjusting of injector pumps beyond timing. I want to learn how to do it correctly and well but finding someone to learn from is very hard. The people I have spoke to locally around where I live seem to be in four camps... 1: The "you just mess around with stuff and screw fuel right up" team. They don't seem to have any real idea what they are doing or consequences of what they are doing. 2: The "you just leave it the way it is and some just go heaps better than others" team. (Not much help if you buy a machine that team 1 has already screwed around with and messed up) 3: The group that think that some people are gifted at making adjustments and tuning everything better than stock standard and can even make them run better without even boosting Hp much. Or if they do boost them up they know where the safe limits are. These people think its a very special skill and don't touch anything them selves. Which is a very fair position that I respect 4: These are the people that really know exactly what they are doing and exactly why they are adjusting each setting. They are very hard to find it seems. I haven't got to watch one in person and pick there brain for knowledge yet unfortunately. It is a skill i want to learn and understand!!! I am currently working at a job building erosion control banks with my 12G grader and it is really a bit small for the job but I think its Hp could be increased safely to do it easier. It is a non turbo 3306 and standard spec is 135Hp... It seems to go pretty well but doesn't blow really any smoke at all under load. If it gets bogged down to almost stalling the engine, it blows a bit as it speeds back up (Step on clutch) but not as its loading up in the first place. This seems a bit odd to me! Perhaps it has already been set by someone that knows what they are doing and behaving correctly? I was thinking about starting a thread on the grader page to see if it is as odd as I believe. It annoys me that I don't yet have the understanding to check all the pump settings... might just have to try and teach my self from the manuals. As a side note i did see you thread about dynamic timing when you posted it and did some reading in the manuals and found some specs and the procedure in the workshop manual. I didn't want to comment because i dont have the understanding to know if what i found is correct at all and it may have caused you more trouble than help. It did state though that if it wasnt within the spec to just re-set static timing again. I was very surprised that like you said no one had any info about how to do it correctly. Any way thanks again to everyone that has offered any help and guidance it is very greatly appreciated !!!!!!!! I will update again if I can workout why the temp gauge on my dozer is reading incorrectly high and what the cause was. Cheers
JAJ… What I can say about IP , is that besides beeing clock work, they are mass produced, mass tuned for different engine applications, and besides the many brands out there almost evolved from Robert Bosch System. Here in my planet we mostly fix Bosch systems, after that Lucas/CAV, very few Stanadyne, and CAT, which are the common brands… but they’re many. Usually a system like CAT , can be tweeked up or down, as by engineering there aren’t much else that can be field tuned, without fail. Of course timing , but timing its just the most important matter and has to be addressed in a particular way, that’s when u need a lot of senses and expertise. And some brands are dificult the get the numbers. Being CAT one. (Secrecy) PM me and we discuss about the fuel and timing matters, also a way to get your 3306 to regular 160HP. regards
Hi guys long overdue update. Still playing around with my D6H. I thought I had the heating drama sorted but it’s been hot here again and the dozer has been displaying high temps again. I don’t think I actually have a problem with the machine because the IR gun temps are reading lower than the gauge and I put a new temp recorder sticker on the top hose yesterday and it hasn’t recorded anything extreme. I believed previously that I had an earthing problem and found some resistance at some of the ground points. I fixed all that and the gauges seemed to read a lot lower for longer but after a few hours still creep up over 100*c I want to install a manual gauge to make sure that everything is actually ok but in the time till that arrives I have a couple of questions I’m hoping people might be able to help me answer. I can’t find in any service manuals I have access to, an ohms chart for my temp sender? 6N-5926. Would like to check that to see what it is reading, have previously changed gauge and sender and made no difference. The ohms reading yesterday after sitting idling for a while cooling down was 80*C on the gauge and 2.5K ohms at the sender but I was grounding at the battery not the sender body (was checking wiring and just took a reading) The transmission TC temp reads about 10*c hotter than it should when the dash light comes on (doing a stall test to get it hot) and I have never had the coolant temp light come on. So I think I have a common electrical problem making both gauges read hot but want to confirm this and then work out why it’s doing it. Question 2 is how does everyone rate the Cat Temp Recorder stickers for accuracy? They seem like a great idea if they are accurate. Can post a pick so people can see them, but P no: 8T2821 Sorry for the long post As alway I appreciate everyone’s input Best regards
Resistance at: 54.4° (129° F) ... 5806 to 7264 ohms 115.6°C (240°F) ... 524 to 586 ohms
Awesome thanks heaps Nige!! Based on that what would you expect to be seeing when it reads something in the normal operating range, say 100*c (212*f) at the gauge? If it is reading higher than actual it has me a bit stumped… ground resistance reads zero and the gauge seems to be getting full voltage from the ignition switch. I think I must be missing something, any thoughts where I’m going wrong? Do you have any thoughts on the temp recorder stickers accuracy?
Sorry, missed that bit. They always seemed to work pretty well whenever I used them.
i have no idea. I searched everywhere and could only find that data I posted above. Whether the sender performance between the two mentioned temperatures is linear or something else I'm afraid I have no idea. Just throwing it out there, but have you considered dropping the coolant and running the machine for a while with cooling system cleaner just to see what comes out of the drain plug.? I would say it's worth a shot.
The sticker will read more accurately on the metal radiator tank than on a rubber hose, the hose is insulating and the surface will be between the coolant temp and the air temp. Next time, try to determine what voltage the gauges are being supplied with, in older equipment there would sometimes be a voltage stabilizer just for the gauges. I don't know if these gauges do that internally, or if there is still a voltage stabilizer on something like this. I'd check the voltage supplied to the gauges, and then sent to the sensor with the wire disconnected at the sensor, both when you first start, and after a couple hours when they're creeping up.
Maybe someone can interpret better than me how exactly this table should be interpreted. I assume the 312 Ohms is a resistor in series with the sender on the signal side.? Inspection procedure: The resistance of the sender must fall within the limits shown in chart at indicated bath temperature with sender in a continuous flow bath with series resistance and applied voltage specified in chart. Bath medium shall be U con oil spec. 50-HB-280X with flow controlled to 228.6 to 254.0 mm per second. Power shall be applied for minimum of seven minutes before inspection.
Yes, that's how I would read it. The 312 ohm resistance added in series is supposed to replace the gauge (and voltage stabilizer if there is one) to test the sender under the same operating range as it would be on the machine. The math adds up. But I'm a jack of all trades, not a cat or instrumentation guy.
There is no voltage stabilizer other than what's inside the alternator. The gauge power is fed directly from the ACC side of the ignition switch.
Thanks heaps for both adding your thoughts Did some temp testing yesterday with my multimeter temp probe dropped in the top tank of the radiator at different times to compare to the gauge and also the temp stickers. I had been putting the stickers on the steel top hose just above the thermostat housing but I did as Delmer suggested and put some more on the top tank beside the inlet top hose. The steel must be thinner there as the temp stickers read little bit hotter. So results are Gauge: Top tank: Sticker: 92. 85. 82 bubble popped 105. 96. 93 bubble popped 109. 99. No change It seemed to stabilise around 110*C on the gauge working hard. Based on my testing it seemed it was safe so I put it up to second gear for a while to see what would happen. It crept up to 115*c on the gauge and seemed to stabilise. So I let it cool back down as I figured I would have to be close to setting the temp light off…. But it never came on. The day was about 41ish ambient. I’ll post pics of the sticker but it looks like it was about to pop the 104*c bubble. The radiator has done 10.3hrs since being blown out and is due but I think this indicates I’m dealing with a gauge issue not an overheating problem per se. We had a 49*C ambient day a few days ago and it was reading between 110-112*c then I think, with a cleaner radiator but I was stopping every now and then and letting it cool off for a few minutes. Would be very interested to hear your thoughts on this data.
I checked the voltage at the gauge but I missed the bit about the sensor sorry. After warm up at first start, full revs 27.36V When hot 27.6V (was varying between 27.5-.6)
Well for the sensor test it says 27.2v so I wouldn't think that at a maximum of 27.6 measured you are a million miles away. I still vote for getting some cooling system cleaner through the guts of the system and see what colour fluid comes out of the drain.
I was going to run some cleaner/flush through the system before but I thought I had it sorted when I found the earth dramas and the client wanted me to hurry up and get the last few days done on his job so thought I’d test it again and see. I have a manual gauge and some Cummins Restore and Restore Plus coming on the mail today. I think I could have a bit of build up in the radiator that if cleaner out will certainly make it better again. I also have another coolant temp switch ordered. I thought it would be good to make sure there is a new one fitted in this situation. The one in there looks good but just to be sure. I also ordered a hydraulic oil temp switch that activates at 102*c and was going to add that on a seperate light to give an early warning that things were getting hot… but the manual gauge should be better anyway I think???
I was typing when you replied. Thanks for the input. Have the cleaner coming today… I want to fit the manual gauge first and test today to see what it reads so I have a base line with it before the cleaner goes in. Apparently the Cummins Restore Plus will remove rust and scale so I might wait till I get the machine done on this job and home incase I have to remove coolers if they get blocked. The Restore one removes other deposits so I might run it first then progress to the nuclear option perhaps??? Re the voltage… it seemed high. Do you think that could be the cause with the gauge reading high?
I wouldn't think so. To get a charge into the batteries of a 24v system you need to generate far more than 24v to force the electrons back in the opposite direction....... Usually High system Voltage alarms on electronic machines come on around 30v and VERY HIGH warnings at 32v. I wouldn't think 27.6v is high at all.
Yes for charging I thought it was fine but I thought perhaps it might be high for the gauge… thanks for clarifying. I miss read you response too, missed the “wouldn’t” in the “wouldn’t think” Ah well I hope this manual gauge will fit and I’ll report back this evening with more data Thanks again.
Another update Did the cleaning flush treatment today. Fitted the manual gauge the day before. The manual gauge confirmed that the electric gauge is out a lot. It looks to be between about 7-10*C lower on the manual gauge, which backs up the other tests. It was still running hotter than it should be at around 103-4*C and the electric gauge reading just over 110*C. The radiator did need a proper blow out but, at one stage I had to free run 10minutes to the next line in second gear and it still went up from 90 (after cooling it down) up to 105*c. It was 44 ambient but I thought this was pretty telling that it needed a flush. After this and knowing I had a gauge I felt I could trust I worked in second gear to see if the light would come one. It did and read about 112*C on the manual and just off 120*C on the electric. This was a bit out of spec I think? Cooled it back off and then worked in first gear again. Today drained coolant put in the first alkaline chemical and worked it for 2hrs and then drained and flushed it 5 times I think it was, till it came clean then refilled with a weak mix of green coolant to test it with. The flushes weren’t a really dirty brown but a milky looking sort of colour with a green coolant tinge. A bit of sediment in the chemical run and a little bit in the first clean flush but bugger all if any after that. I think it made a difference and well worth doing but won’t know exactly how much difference till tomorrow. Depending on how it goes now, I might wait till it gets home and then run the acid based cleaner as well. I want to flush and swap over to Cat ELI as soon as it gets home, think that will be a good move?? I can post pics of the coolant and flush samples if anyone wants to see them for diagnoses purposes?
Got to test it out today. Seemed to take a lot longer to heat up and then stayed around 92-95*C on the manual gauge until the trans temp finally met up with it. That took a lot longer than normal too, but once it caught up it crept up to 100. Comparing the electric gauges the trans and engine temp, the trans still stayed 5-10*C hotter and stabilised. It was only 38*C ambient today which would have helped. So I think the flush certainly helped but it has me a thinking now that perhaps the trans could be contributing still. I thought I had that sorted but wondering what you guys think? I blew a hydraulic hose (I think going to the valve on the underside of the main hydraulic pump) and have to remove the belly plate to get access to it. While I’m under there I thought I might pull the scavenger line off the torque converter to check the screen. My idea is the converter might not be draining properly and slowly building up…. not sure if this could cause what I am seeing but thought worth checking. Any ideas what I should look at next is most welcome! Also Nige I wanted to pick your brain about transmission oils. The local Cat dealers tell me to only ever run sae30 oil but the book says that for higher temps sae50? What would you recommend? Any ideas or thoughts most welcome Thanks for the help guys!!!
What's the ambient temperature range (min/max) in your location.? TBH I used to be a big believer in SAE50 in higher ambient temperatures but not so much now. The downsides of a higher-viscosity oil outweigh the benefitls.
Ah ok that’s what the local Cat guys said too. It’s pretty rare to have a day time max temp as low as 10*C in winter, usual cold days might be 15-20*C. Over night temps do get around zero, rare times down to -3*C or so. Summer temps 40-45*C is pretty standard and high 45+ up to 50 in heat waves.
An update on the saga. I have the machine home now and so time I can get into pulling stuff apart. I had rechecked the trans pressures while it was still working and found the Torque Converter pressures were getting very low when it got hot. I left the gauge on the TC while working and it seems to get lower the hotter it got, from in spec cold to low hot. I know that is what happens as things heat up but I figured the outlet relief valve needed to be checked, cleaned and adjusted. Pulled the outlet relief valve off and apart last night and it has only one spring and no shims. The parts diagrams say it should have an outer and inner spring and lists 5 shims. Nige stated on another tread i was watching that the listed amount of shims is the starting point so I will start from there with new springs. I am hoping this is a big part of problems. Will order new springs and enough shims to do any adjusting that is needed as well. I think its interesting as the images in the shop manual show only one spring in the disassembly pics, but the parts manual clearly show two springs, so not sure if this was updated at some stage?
Buy 5 shims by all means + all the other replaceable bits of the converter outlet relief valve, not just the spring. I would suggest that you start with maybe 3 shims and go up or down from there to achieve the specified pressure. Remember that you have to test the converter outlet pressure with the oil at normal operating temperature, around 80C as a minimum. I’ll have a look at the parts tomorrow regarding the springs, etc, as it applies to your particular Serial Number.
Thanks Nige I was thinking about getting a full new valve but there is a bit of a wait for one and just checked there is for a valve spool as well (might call and check air freight). I will have a good look at the surfaces today but, I was thinking do new springs and seals and see how it went. I figured it would be a cheap way to test it if it looked ok otherwise, but would you replace the spool as well? If the surfaces (body or spool) were questionable I thought get a full new valve and start fresh and remove all variables. I will post a couple pics later Re testing, I think with the temp gauge reading out, I was testing too cold before and it was only just in spec I think.... but i cant find my sheet from testing it when we did the pump. Ill try and find my numbers but the testing recently seemed like the valve wasn't closing and the pressure was going up and down with the revs.
The plot thickens…. The part number on the valve is not the correct one for my machine and says 42psi on the tag. The part number should be 9w-5596. I found a diagram online for this valve (3T-6607) and it seems to show what came out of this one and does say D6H but Cat no longer lists it. The valve spool looks ok (no scratches) but the body has had some scratches honed out it seems and a little loose. Disregard the fleck of paint in the body that was me and not in there when it came apart. Might be safer to get a full new valve and start fresh I think! It has a remaned torque converter from some stage so I wonder if the valve came with it from its original home.
Your 3T6607 valve updates to the later 9W5596 so I would say your assumption that the valve came with a reman torque converter is right. This should not affect your torque converter temperature though. The outlet relief is there to control the minimum pressure, not maximum. The system relies on getting a large volume of oil to flow through the torque converter to carry away the heat to the cooler. This large volume of oil then goes to the transmission lubrication system, hence these questions: What torque converter outlet pressures are you getting? What is your transmission lubrication pressure at high idle?
Hi Cmark Thanks for posting. Found my videos of the most recent testing. Torque inlet pressure (stalled 3 gear hot oil): 53 psi Torque converter outlet (stalled 3 gear hot oil): 30 psi Transmission lube pressure (not stalled high idle hot oil): settles at 32psi I was thinking that if the pressure was to low in the torque converter that could mean it might generate some extra heat from not enough resistance... I could be completely incorrect though, what would you expect that could cause? Very interested to hear what you think about the pressures. Thanks for your help.
Low pressure should not be a cause of overheating per se. It is more of a symptom, indicating low flow not taking enough hot oil away to the cooler. Low pressure means either one of two things: 1. low flow which can't keep up with the natural leakage in the system. 2. Correct flow but too much leakage in the system. Have you checked main relief and priority valve pressures?
Yes I have checked the pressures before and all others were in spec then. I need to recheck them all again to make sure now though. I have been troubleshooting a problem with my loader’s transmission as well and I have got the two machines a bit mixed up with the required specs so I do apologise. I have mixed up the trans lube pressure spec for certain! I thought it was 27psi +-7.5 but I rechecked the spec sheet and it is 37psi +- 7.5 so you are absolutely correct re low flow with that in mind. The oil was over 100*C (can’t remember exactly) when I got the trans lube reading so I thought that may help account for the lower pressure. Not sure how much though? So I think I will start again once I put the TC outlet relief valve back on and with the oil about 80*C (think that’s the spec per the testing procedure, will double check) and get all the numbers and post that. I also want to check inside the back inspection plate on the transmission for leakage on or around the control bank to rule that out.
So I installed the new springs in the Torque converter outlet valve and started with 3 shims. Then reassembled it to check. Stalled @85*c = 54psi @100*c = 53psi Lube pressure after driving around for a while to heat everything up properly. @85*c = 40psi then dropped back and stabilised at 36psi high idle. So I think that should be almost spot on for the lube pressure and I need a couple extra shims in the TC valve to bring it up to exactly where it should be. It is now in the allowed amount though. 60psi +-10psi The tractor feels a lot more responsive and seems to drive easier at lower revs ( if that makes sense). So I think and hope this will make a huge difference, but need to work it hard for a day and see. The ambient temp has dropped off for autumn so it may not show up till next summer if it is going to get really hot again. I haven’t rechecked the other pressures again yet but will do it and posted them when I get a chance. Interesting to note it seems like from what I read that the D6H series 1 had the TC outlet valve like I have, set at about 42psi. The part numbers appear to be the same for the valve body, spool and even the big spring. Seems it was changed to a double spring setup at some stage (I assume series 2) and the spec raised to 60psi. Would be very interesting to know why they did this if anyone knows?
See attached Servie Mag from 1987.
Very interesting!!! Thanks for posting this!!! I am mentally wired to want to know “the why” behind everything. So this satisfies my hunger for information on this matter. Also interesting is the pressure spec for the new valve assembly in vehicle is 56 +-2psi and the testing and adjusting in the machine manual is 60 +- 10psi. I assume it might be best to aim for the tighter spec of 56psi? The bigger amount in the machine manual allows for the variables of each machine and oil temp “in service” I expect, not sure. What would be best practise for the adjustment 56 or 60psi?
That SMag is over 35 years old. Things can change in that time span. I would use the newer spec but quite frankly a lot depends on how accurate your gauge is when measuring pressures this low. I think the quoted Cat gauge for TC outlet pressure measurement is 125psi max, Personally I’d be more comfortable with one that maxed out at 75 for better accuracy. Either way if a cheap inaccurate gauge is used you’ll probably be doing well to get the “real” pressure within +/- 10psi anyway, despite whatever the gauge might show.
Yeah I have cat gauges but I think they are 145psi and 575psi, I have the part numbers. When I was at the hydraulic shop getting all the parts to put the rippers on this machine I got another set of STAUFF gauges in 86psi and 45psi so I can test stuff more accurately at the lower pressures. They seem high quality. I was using the 86psi one on this but had to be careful while it was cold not to go off the dial now. So I think the valve may have been stuck or the spring was buggered before. I got the 45psi gauge to test the trans lube pressure on my loader transmission to make sure before I commit to pulling it out. I should start a thread for it actually and see if anyone has ideas before it comes apart.