Got a hot one (sometimes). This machine will every so often go thru a spell where it runs over-temp. Does not always blow coolant, but can. Even in cooler weather this machine will overheat. The fan seems to ramp up and down normally, when it isn't overheating, and does run full speed when it is. If it sits idle, it will return to normal temp relatively quickly, but back to work it is hot again in just a few minutes. Dealer has looked at it a couple of times, and says the sensor is good, fan control valve was removed and cleaned/inspected....called good. It doesn't have to be worked hard to get hot. Nothing in codes really helps. Just records instances of high temp. The radiator is clean, having been blown with air, and washed with water. Never really gets in a dusty environment, so very little dirt or sawdust (it is in the mulch yard, but only a little) ever shows up. I don't think it's an airflow issue. It's too random to be a clogged radiator core, I'm thinking. I'm thinking maybe it's some sort of water flow issue though, but I don't really know how to make that call other than a clue in the temp drop across the radiator. I haven't checked for collapsed hoses. Probably other things I've not thought about. Maybe stat is sticking? I'm open to ideas. SN is 1T0700KXAJF326182 if that helps. For all I know this model has a known quirk.
Sticking thermostat maybe or the rad. needs to be cleaned internally?
Could be. The machine has ~1300 hours, and the coolant was changed and flushed at 500. It's currently clear and clean. I can't say for sure about the flow. I used to judge flow when I worked on radiators by blocking the outlet, filling the radiator then unblocking it. After a few, it's pretty easy to see the difference in flow before and after vatting/rodding. I had family in the radiator business. I don't really want to pull this one to do that, and I'm not thinking I can get to the inlet/outlet very handily to try it. I may have to unless I can gauge it some other way.
The rad. shouldn't be very bad with only 1300 hours. I'd check the thermostat. Is the fan belt tight and not slipping? Wondering if it's a water pump problem.
Yes, the belt is tight. I would tend to agree about the radiator. Same with the pump impeller. Seen a few rusted/washed off but the cooling system is clean so I don't think it's corroded off. If it had cracked or fallen off this overheating would be consistent. It was run a couple of hours late friday afternoon and was fine... after having hot flashes twice earlier in the day. I might opt to replace the thermostat just to eliminate it.
I agree thermostat would be my suspect…that said, have you used an infrared temp gun to shoot temps along the radiator in/out to verify temp drop?? With fluid change done 800 hours back, I highly doubt your dealing with possible air pocket(s) causing erratic operations/temps Could always pull the current thermostat out all together to see if it changes its attitude/operation…would also allow you to use the wife’s favorite pan to test it in hot water to see how it reacts!! Curious if these machines use a “dual-acting” thermostat??
No Dan, I have not. It was run yesterday and all was normal. Well, temperature-wise anyway. Even at this low hour reading, the right hand track idler has lost a bearing. It's parked for now. I'll be looking for a replacement. I have not looked closely enough to see if the bearing is serviceable, but that's ahead of the thermostat. I would just yank the stat, but I know how things work around that place and it would end up running all winter without it. I don't think I want that to happen. I have no idea if it has a dual stat. I'll be posting back on this. Oh, and I have been given my very own testing pan! I have a hot plate that is used for thermostat testing. Only trouble is that I've had some that didn't open at 212°/100° and out of curiosity, I'd love to have run them on up until they did....but can't without a pressure cooker!
Couldn't you heat them up in antifreeze to be able to exceed 212F. It is the pressure that turns the antifreeze mixture up to a crazy 260F or close to it. From what I recall antifreeze will boil at a higher temp than 212F even without the pressure cap. Simon C
Yes Simon, that's true. I don't remember the temp curve right off, but it's true that the bp increases with concentration of ethylene glycol. I remember that a 50/50 mix generally yields the lowest freezing point, but I'm not sure of the boiling point. If I do that test, I have a candy thermometer in the solution anyway. If I get a stat that won't open at <212°, unless it is specified to a higher temp, I consider it junk and replace it. It's just idle curiosity that makes me want to go higher...no real legitimate need.
It is a hydraulically driven fan. Has that circuit been checked, especially when it is running hot? Does the fan reach maximum speed when the fan control solenoid (or coolant temp sensor) is unplugged? It should be a minimum of 2000 rpm @ fast idle with the hyd oil temp @ 140-160*F. I would perform the test when the engine is overheating. A temperature drop across the radiator would isolate a coolant flow problem from an air flow problem.
In some engines they will run hotter with the thermostat removed.
Had this problem before.....fan speed and a super clean radiator core is everything
@mg2361 Yes, the local dealer has had 2 different techs out at least three times and they did do a hot check. The only fault they found, to the best of my knowledge, was a dirty connector on the solenoid controlling the hydraulic supply to the pump. One advised that we should tear that valve down and make sure it was not full of trash, which we did and found it clean. I have not checked speed with my strobe yet, since it only got hot twice on Friday, and ran a bit normally after cooling down that afternoon, then was normal on Monday. Yesterday the idler issue turned up and it was not run. Since it was not hot, I did not use my IR gun to check it yet. @oarwhat I've seen that. Unrestricted coolant flow does not have sufficient dwell time in the radiator to give up the heat. I rarely remove the stat on anything other than for testing, but I do watch for that. @Vetech63 The radiator has been blown and then lightly pressure washed, with little to no change, I am not thinking internal, since this is fairly random. Thanks all!
On the fan control valve thete are 2 electrical plugs if I remember right 1 is the proportion control and the other is for reverse. If you unplug the prop connector, the fan should go to full speed at engine high idle. I would check that speed first thing and make sure its in spec. Even a couple of hundred rpm makes a huge difference in cooling. When they are working right, it sounds like a helicopter taking off lol
Well, I can't say it's that loud, but then I'm 90-95% deaf. I'll get a helper. And strobe it for speed. I don't recall the connector arrangement for sure but I think you are right. When I get the idler back on it I'll run it and try unplugging it while cold, the fan should kick up to high regardless, it sounds like. Been up in a CH-47, but that was before I went deaf lol!
It needs to be speed checked at operating temp
I intend to, but would it not be telling to check it with/without modulation by the valve even when cool? Or did I misunderstand?
You can check it cold but hot oil leakage through the internals will be a lot more prevalent for accuracy
I can see that. A simple function test yes/no should show even cold though, true?
I thought that too. It may show if the rpm is really way off, but even a 200 rpm drop will effect the cooling and that is hard to tell by sound. Hot oil leaks through places it shouldn't more than cold oil.
On the idler for this machine, is there a big difference in the "Maximum Life" undercarriage parts? Should I be looking at doing both sides? Or are the idlers even interchangeable?
Anytime we have a machine with a fever we add cowbell you just got to add more cowbell !!!!!
More cowbell!!
OK guys, I need some idiot proof advice. I need to replace an idler on this machine, and I have no clue how to break the track. I've read a bit on JD's and there seems to be a couple of methods used to pin the links together. I have not pressure washed this machine as of yet, but that should happen tomorrow so I can find the master link/pins, provided this machine has them. I'm hoping it does.
Its probably a clip. Look for a single solid link in the chain. The bolts going through that solid link grouser pad are what's holding the track together
So the master link will be pretty obvious once I wash it? I read about the clipped pins. Supposed to tap them towards the clip sometimes to allow clip removal, then drive them back out. This would be the tapered style? Biggest on the inside or outside?
Its very obvious if it a clip style link. There is no pin to hit.
OK, I gotcha. As much mud as this machine has on it, all the links look the same. Looks like a bit of a pain to get that link in the best position to detach. I have the machine on concrete at the moment, but I suppose I'll have to move it forward or backward to position that link in the right place. So after releasing that link, I'll hook a chain to the pads near the short end and work it forward and down to the ground. The idler bracket looks like it will slide out the front, more or less. All I have off so far is the rock guard and I see the spacers and shims holding things together. I don't know the common failure mode, but on this idler, either the bearing has completely failed, or the axle pin...something has allowed the idler wheel to visibly shift rearward about 1" or so. I can't see yet what is going on with it, but it's obviously not centered on the bracket boss which I believe to be roughly centered with the shaft support. Even the sheet metal rock guard has been running on the idler wheel and eaten into it over an inch. Odd for 1300 hours, I think. I guess it depends on where it's been run though.
If you are looking at the idler, put the solid link at the very front of the idler and break the track there. The lower part of the rail will lay against the ground and you can use it for a guide sliding the idler in and out . You can then start the machine and back the upper part of the track back far enough to gain access to the idler yoke bolts. No need to remove the entire track for an idler job
I was thinking to do just that, or break it slightly above center on the front of the idler. I was wanting as much of the track laid out on the ground to slide it out on. So nothing actually retains the bracket at that point? It's not bolted to the tensioner? Or is that what you meant by the idler yoke bolts?
Unbolt the idler from the adjustment yoke bolts.
OK...think I got it. Thank you!
Looks perfectly executed to me. Give that man a cigar!
That one of the young helpers. Piece of cake once everything fell into place. It split nice and easy. Parts inbound in a couple of days. Then back to the fever. Heavy rascal. Thanks for the help!
Use anti-seize on the bolts for the master link. There should be an initial torque and then so much of a turn to tighten the bolts. It's very important they are tightened properly.
So they are TTY fasteners? I’ll need new bolts then. I don’t have the specs yet. Guess I’ll be talking with Doggett. Anti seize is a given. Use Never-Seize typically, nickel based. Unless there’s a preference for copper for some reason. That is have to source.
The whole idea of torque-turn on master link bolts is to get a consistent clamping force on the crocodile link, so I don't think the hardware is TTY; certainly Cat hardware isn't. Depending on the condition of the hardware that came off it may pay you to replace it. Especially true if the bolts heads are worn at all. Anti-seize on those bolts goes everywhere, the shank, the threads AND under the head of the bolt.
Back to the mystery overheat. My 544k would, once in a blue moon, throw an overheat. But, the cab heat was nearly non existent. Because of the hydraulic fan, and convection, it seldom overheated. The tattle tale was one cold heater hose, which led to a failed plastic water pump impeller. Same 6068 engine as yours.
And on all personnel within a 3 meter radius. The bolt heads are in good shape but I’ll replace them anyway. Cheap insurance against trouble. TTY theory is to provide that controlled clamping force. The yield strength of the fastener is the primary determining factor in how much stretch it takes to get that pressure yet not exceed the ultimate tensile strength of the bolt. It stays in the plastic deformation zone, just beyond the elastic zone. Thanks guys!
Taking that one step further it all depends on how close to the material yield point the final clmaping force is actually designed to be. One some hardware the service manual will state "remove and discard the hardware". On other hardware, even though the spec is also torque-turn, it will not. The latter hardware is always reusable provided it meets reusability guidelines/criteria. Cat publish a document on this, I don't know if any other OEM does. Undercarriage hardware for me falls into the latter category. It's torque-turn because of nicks, scratches, dirt, etc. These are all factors that can cause large variations in hardware clamping force if the spec was a simple torque but will not affect it nearly as much if the hardware is torque-turn. Generally the final clamping force on undercarriage hardware is nowhere near the material yield point of the hardware.
Would fasteners torqued to yield fail if additional load is placed on them? Track pad bolts undergo a lot of stress.
Install new bolts..........thank me later.
That's kind of a loaded question (pun fully intended). Yes, any bolt can fail at excessive load, of course. The design intent is to load the TTY bolts to a certain level that is not anticipated to be exceeded under normal conditions. They will stretch a predictable amount under the normal load and after that, if the ultimate tensile strength is exceeded, they will fail. TTY bolts are not really stronger or anything special other than given that stretch near their maximum tensile zone. It provides a very consistent loading to aid in a very stable clamping pressure and this helps with critical assemblies such as heads/gaskets/blocks. I believe track shoes are not all about that, but rather as Nige aptly noted, other factors such as surface imperfections and damage typically seen on those mountings that would interfere with getting the most from the bolts. Nothing really to seal, and unlike heads, there is no large, flat, critical surface.
Well, today was a bust. The idler I brought in, admittedly a non-OEM (trying to save a buck), was incorrect. The bracket/frame bolt holes would not line up with the yoke on the tensioner. I am convinced that the vendor supplied an incorrect part. Even with the SN, the idler I received I believe is not for the MaxLife undercarriage. Dimensionally I see a definite difference in the shoulder width of the wheel. The supplier was very responsive and will send another, but asked about the MaxLife...I honestly do not know if that machine is so equipped, but I suspect so. I know it cost about $500 in freight to get it here, so I'm not very happy. We shall see.
If they got it wrong, they should eat the freight
I'm sure the idler cost enough the supplier should cover return shipping.
Supposedly, another is on the way, and an RMA is issued for returning the first one. I have not received that email yet, but hope so. There's probably not so much markup in it to cover the freight 2x, but that's not my problem really.
You shouldn't have to pay for their mistake.
I agree, Dave. I don't plan to. This is the first part I have bought from this supplier, and they came highly recommended. I've give them this mistake provided they make good on it. I have a few more parts to quote and I'll let them price them out. If they work through this one I'll stay a customer.