Cat D6H LGP 2 overheating engine (coolant restrictor?)

[Delmer]

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.

 

[SlatcoAu]

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.

 

[Mobiltech]

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.

 

[JAJ]

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.

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!!!

 

[JAJ]

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.

 

[Nige]

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.?

 

[JAJ]

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.

 

[JAJ]

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?

 

[tctractors]

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

 

[Nige]

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.

 

[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.

View attachment 281397

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

 

[Nige]

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.

 

[JAJ]

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.

 

[tctractors]

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

 

[Nige]

I wonder what other mods are done to the engine to complete a 'Cold Climate spec',

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.

 

[Mobiltech]

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.

 

[tctractors]

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

 

[JAJ]

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!!!!

 

[JAJ]

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??

 

[Mquinista]

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.