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Cat D6H LGP 2 overheating engine (coolant restrictor?)

tctractors

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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!!!!
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
 

JAJ

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Owner operator of small fleet
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
AE7C4152-76CF-4E60-A493-FB3A1157C08D.pngThis 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.
 

tctractors

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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.
 

Delmer

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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.
 

Nige

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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.
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'd like to see if the pulleys and fan are appropriate for the high ambient temps, or if there are better ones available.
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.
 

tctractors

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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
 

JAJ

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Owner operator of small fleet
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.
 

Delmer

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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.
 
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JAJ

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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!!!
 

Nige

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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……..
 

Mquinista

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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.
 

JAJ

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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
 

Mquinista

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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.
 

JAJ

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Owner operator of small fleet
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
 

Mquinista

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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
 

JAJ

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Mar 22, 2022
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Australia
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Owner operator of small fleet
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
 

JAJ

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Australia
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Owner operator of small fleet
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?
 
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