Hello all, I again am back to diagnosing coolant issues with my D6b. Yesterday I fired the ole girl up for a few property repairs, after full checks, Fuel, Oil, Coolant, and gear oils. The machine fired up instantly after sitting for a year and a half and I made progress for about 45 minutes when I notice fluid on the hood near the radiator cap, and instantly I instinctively looked at the temperature gauge noticing it was running about 220-230 degrees F. I immediately lugged the machine to it's parking place and shut it down. I noticed coolant inside the front portion of the engine bay, outside the front of grill, on hood and dripping down to the ground. I instantly thought, check the oil and breather for coolant and contamination. None was found. only in the places first noticed. I put a brand new thermostat in year before after doing head work on the machine. For the first year after the head work the radiator stayed completely full until today when I had to add 2 gallons of coolant. I'm not certain I have a head issue but the situation didn't occur until I began running higher RPMs while pushing brush and trees across the property. I've looked back through all my diesel mechanic books but never experience this before with a diesel. Reminds me of a car on a long family trip the starts boiling over like a thermostat stuck. Any other ideas? Sam
With clean water clean the leaked coolant up, then blow it dry. Top the radiator off and put a pressure tester on. You apparently have an external coolant leak, you need to figure out where it is leaking first. Radiators, hoses and such are highly probable culprits for the leak you are describing, I wouldn't get excited about heads such just yet.
Yeah, probably will after this freezing weather. We know the fan pushes air rather than drawing air on these machines, which would explain the coolant on the outside grill, but fluid on top of the hood is the most baffling part to me. I have a water pump seal kit so I may go ahead and do that as soon as I test pressure. I hope it's not the head, the D333C head is very few and far between for this machine.
I agree with the pressure test/leak detection… I’d also add once you have side panels off, make sure you don’t have a mouse colony in your radiator area…1.5 years and cold weather…their nest could have killed your airflow, chewed hoses/belts, let alone what their urine/poop does to parts…bright side at least you know they didn’t damage your ECU/DEF systems I have a D333 too; I’m pulling for you!!
If the pressure test doesn't show any leaks, the next suspect would be a clogged radiator. Unless something obvious, like the fan belt falling apart from age. For overheating like that, I'd let it run normal speed with no load for a couple minutes to see if the temp drops, even if it doesn't drop right away, a minute or two will equalize the temps somewhat for a better outcome than driving it and then shutting down.
I am seeing the radiator cap as a suspect, but I am not saying that out loud yet . . .
I just ordered a new radiator cap to knock that suspicion out early, but will be overhauling the water pump and testing the pressure too. Thanks for the replies.
I'll take water pump for $200
D6b is a D333a engine, not a D333c. a engine has belt drive water pump, c engine is gear drive water pump.
I don't know why I said C instead of A, I learn this from you...LOL!
Could someone cross reference part number 4F2478? My parts manual shows 8H8719 but the part number on the old radiator pressure relief valve is 4F2478. I have removed the valve after checking the leak and determined the radiator cap seal is dry rotted, but PRV is allowing fluid to drain after heating up. Coolant is leaking from upper radiator area and I suspect cap and PRV. No leaking at pump or hoses that I can see. When I removed the PRV it was slightly stuck but compressed easily after freed up.
4F2478 pressure relief valve services to 5S1218 in its latest form. 8H8719 is the complete Relief Valve assembly including the cover, gasket, PRV, & hardware.
Thanks Nige, you never fail!
FYI with all the upgrades of the PRV Part Number it may be the case that the 5S1218 (which is the only Part Number available now, all the others are obsolete) requires a different cover to make it work. I've looked everywhere but can't find any conclusive evidence yay or nay, so be prepared.
I have found 1 refurbished part on ebay, but not sure about it, it's listed $45. that is the only one anywhere that I can find. the 5S1218 is available much cheaper, but smaller.
I have no idea how anyone would refurb something like that particular PRV. This is the best I can do for the installation. The Parts Manuals only go back as far as D6C.
Try searching for 2S2036. Back in the day it was a direct replacement for 4F2478. It has also been discontinued by Cat but may be available aftermarket.
I went out to my machine this am (68 D5 with the D333) to see/remember the rad cap/PRV setup… looks like our machines run the same PRV cover/cap, along with the same strainer… But my parts listing shows the easier to find PRV. To me it looks the older PRV had a larger metal flange that the cap would bolt thru…the 5S1218 looks to just fit inside the cap…curious if you have any pics of your setup? Oops, I was looking at the part numbers from Nige’s post and realize that’s a D6C and you have a D6B… Maybe a swap of PRV cap (5S1211) too??
I found this. Listed as "7S4327 Pressure Relief Valve Group. Provides Field Replacement for 3H3413 Cover" - which if I'm not mistaken is the Part Number of Cover you have on your tractor. 7S4327 includes the 5S1218 Part Number of PRV. It might fit your D6B but I would not guarantee that.
Yours looks just like mine.
this is what mine looks like
OK, so your PRV has an integral plate built into it. If you look at the illustration of the 7S4327 it includes a separate 7S4252 Plate (Item #4) in addition to the 5S1218 PRV. The Plate supports the bottom of the PRV. The two items put together replace the one-piece 4F7428. The only caveat is that it might also require the 7S4249 Cover to replace whatever Part Number you have on there right now.
Sam1734, if you look at #27 on my parts diagram, it shows 2 gaskets with a plate (5S1213) sandwiched between them (I didn’t notice it on the first look) …I believe if you have same top cover (5S1211) as me, and you find (or make) a plate to take up the missing space that your full flanged PRV provides; that the “newer” 5S1218 PRV will work/fit in your machine. If/when you open yours up, I’d luv to see some pics of the screen and area the parts fit into- but if pics aren’t possible, no big deal. I know your still working thru troubles so I don’t want to slow you down… I’m looking forward to the conclusion (aka cylinder head is just fine!)!!
I have to remove a broken bolt on it so yes I will get a picture of it. No hurry to get it finished.
Took this picture today, not sure if it’s what you were asking to see.
What Part Number is cast into the PRV cover.?
Nige, for once I am dumbfounded. That cover is the only thing I’ve found on this machine that doesn’t have a part number.
That's strange-ish. I expected it to have a number cast into the top just like the one on D5Dan's photo. Maybe not the same number as his but a number nevertheless.
I was certain I could get the numbers in just a few minutes but had to bring the cap in the shop and remove paint and rust only to find a solid brass stamped plate with no markings at all, however I just discovered and possible culprit of my leak upon your request. As I was inspecting the cover, I had to remove the gasket and noticed that the port where the valve and overflow meet the gasket was weak and deteriorated like a "blow out". Was it common in those years to use stamped brass plate like that?
No part number eh; how do your dimensions line up to these?? Overall width of cap: 3 3/8” Middle section width: 1 3/4” Cap thickness: 7/8” Middle section bump-up: 3/8” Funny, I never noticed the discharge/relief hole in the side of cap(!)…one more thing I’ll try to include in my scan. Sam1734, can you post some pics of your cap, both the topside and underside- and it does have a discharge hole, right?
Oh your PRV cover is absolutely more heavy duty than mine. I'll get a pictures shortly.
Nige, you can see here what I was talking about it having a stamped brass plate for a cover
I cut a deal with the person on ebay for the PRV. It’s not remanufactured . It’s actually a new part but old stock that had to be listed as refurbished.
Is your machine a D7 or larger?
Sam, from the photos I can see that if you wanted to install the latest 5S1218 Part Number of PRV you would not only need the plate that was discussed earlier to support the PRV on the bottom side but also the new-style (thicker) cover along with longer bolts. That makes sense because the whole assembly is listed as “field replacement for”.
1968 D5 with a D333 …but I believe a good bit of my parts would/could/should(!) cross to a D6B. Thanks for getting me back out to my machine, that “project” got put on back burner
Welcome! LOL ! I am multi tasking myself. I'm also in the middle of a car restoration for my grandson.
I just put new gaskets on and the old PRV and ran it a while, about 20 minutes and the temp wouldn’t get over 190. But the coolant was still leaking from the new cap like it is overflowing. Water cool to touch in radiator. But seems to be circulating. Maybe thermostat isn’t reaching temperature to open. I’m still baffled.
Coolant leaking from the radiator cap or from the weep hole in the PRV Cover.? Did you check that the weep passage was clear when you reassembled the PRV.?
Yes it was clear. And the radiator cap is leaking. Kind of like when you have water in a glass jar and overflowing after the engine starts
Kind of leaks out like a water level in a clear hose but when you look on the inside engine bay the water seems to be pouring out from the top
Radiator too full to allow for expansion.?
Was the system ever pressure tested?
Just figured the main leak, the radiator cap seal doesn’t seal well so I added another thicker gasket which stops the leak but water is overflowing through overflow tube and temps getting up to about 240
Not yet waiting for pressure testing equipment
What happens if you run it at an idle at operating temperature with the radiator cap off? Also, where did you get the new radiator cap from?
Only circulating and temp stays normal
If it reaches normal temperature the cooling rises to the rim of coolant nozzle and overflows
Again he asks, is there any possibility that are you overfilling the radiator.?
Almost sounds like the system is air bound . . . ? Run it with the cap off for awhile, let it find its level. Put the cap on loose and work it a bit. If everything is good it should puke coolant out until it finds its level and then stay there. Then put the cap back on and see what happens. The cap not sealing is a problem though. Either it is the wrong cap (local auto parts store matchup attempt?) or the radiator is pitted or otherwise bad where the cap seals.
Could be. After I done the head work I refilled to manual specs which I think was 7 gallons. I don’t have the manual with me at the moment
I will try that, and no I ordered it from regal. However it was different from the original cap. It was cast iron rather than the steel plate original. I suspect the stud inside the radiator might be bent a little because it wasn’t seating correctly. I discovered this when I removed it to check levels after I allowed the coolant to dry on the hood.
Nige would probably have more insight about the cap and stud in the radiator. I have very little experience with stuff that old . . It does sound like you have the wrong cap though. How much run time has there been since this head work? Generally speaking the spec for coolant capacity is a reference to indicate how many jugs of coolant one should dump in before he starts paying attention . . .
I’ve not put over 100 hours since, just minor farm work.
All capacities listed in manuals (Cat ones anyway) are approximate refill capacities only. Systems should always be filled using whatever device the system may have for determining the correct fluid level. I may be wrong but in radiators such as this one I thought that the correct level was just a hair higher than the top of the tubes looking down into the top tank. Enough for the coolant to circulate in other words.
Was it the same Part Number that you have in your Parts Manual.? Is that the old or the new cap in your photo in Post #34 on the previous page.?
The radiator has a flat plate inside that the stud is mounted and unable to see the radiator.
Yes sir it is.
See the diagram below. Does your radiator have a vertical tube below the neck. If so the coolant is filled until it is about 1/2" below the level of the tube.
No
It looks like a baffle inside the top of the radiator and unable to see anything but the flat plate inside. Filler neck is made into the top of the radiator top.
This is more like what I'm seeing.
Ok, I just got the new PRV and immediately I noticed that the spring is much stronger than the old part, and the new part has a seal for when it closes off. The old part did not have a seal period, So I assume this is a contributor to the leaking through the overflow. Going to run it without the radiator cap this weekend after I install the new part.
Why would you run the engine without the Cap in place? your water will be on the floor in a few moments, if its a big screw on cap it needs to be fitted and screwed down firm, the coolant level needs to be correct, your new prv will take care of things, if the main cap is not tight water will pour out fast with the engine running. tctractors
Is there a special attachment to pressure test the radiator on the D6B?