chem_man

Well, I would just look at the temperature that the Engine Coolant Temperature (ECT) sensor is reporting to the PCM to make sure that it is reporting the right info. By right info I mean that the ECT is showing near ambient temperature when the engine is cold, and then it increases fairy regularly as the engine warms up (no sudden 20 - 40 degree jumps) until it reaches normal operating temperature. Trying to make sure that the ECT sensor is not reporting obviously erroneous temperatures.

Another thing you might want to do is to flush the radiator from the engine side out with a garden hose and a nozzle to flush away any build up of dirt, bugs, etc., that might have collected on the fins and is not allowing a good transfer of heat from the radiator when the air flows through it.

If this does not work and you are still overheating, then you might want to consider replacing the radiator.

Good Luck!

jfmorris

In his first post, he said he had "put in a bigger 3 coil radiator", so it seems the radiator has been replaced in chasing this problem.

Something I will ask, just to ask. @Maydog you do have an OIL COOLER on this engine? I ask because my two 1500's (1996 and 2006) did *NOT* come with the towing package from the factory, which means they do not have the auxiliary oil cooler. Just the transmission cooler that is built into the radiator. I think that could make a big difference when towing. The only truck I've had that did have the oil cooler from the factory was my 2003 Yukon.

Maydog

Good afternoon Jfmorris, I hope all is well. Yes I did replace the radiator chasing the issue, and yes my truck has both aux cooler on the front and the cooler on radiator.

Maydog

Good afternoon group, hey with the problem that I'm having with my truck, could this be an indication of a more serious engine problem? Head gasket etc...? It just seems to me that this engine is heating up excessively. If I didn't think the strain would cause issues for my 1500 I would just continue to pull my camper with it. Although it pulls it fine on flat roads, but when hill come into play it struggles and strains. So I stepped up to this 2500HD and but I'm not having these heating up issues. Once again, any and all suggestions are welcome. So earlier I read where someone suggested bypassing the radiator cooler and just use the aux tranny fluid cooler. What are you all thoughts on this?

jfmorris

Ok, let me be a little more clear. On that truck, you should have several aux coolers. There is first the transmission fluid cooler, then I think all of them have a power steering fluid cooler, and then you should have an engine oil cooler. The engine oil cooler is what I am asking about there. It usually routes to the engine block maybe near the oil filter. Those lines are a source of oil leaks, and on some older vehicles folks "delete" the engine oil cooler and put a new oil filter adapter on the engine, as its only needed if you are towing big loads. I just want to make sure you have the actual engine oil cooler. The transmission cooler will keep the transmission cool, but you are looking at issues with the engine temp, so it makes me wonder about the engine oil cooler...

Maydog

Good morning, @ Jfmorris, I'm asking this for clarity. But when you asked if I had an oil cooler, were you referring to the transmission fluid external cooler or an engine oil cooler?

Maydog

Well let me put it this way, I'm not for certain that I have an engine oil cooler on my truck. If you can give some details, maybe pictures or describe what it looks like then I can check for one.

Maydog

Good morning everyone, I'm just giving some updates for the group. I have replaced the following: radiator, water pump, lower temp set Tstat, fan clutch, fan shroud, and I added an aux fan. I'm still facing the same issue. If I run my a/c and towing, or if I let my truck sit at idle long enough; the temp gauge will run into the hot range. I checked the temp on my scan tool to see if it was matching what the temp gauge was reading and it was a few degrees different. If the temp gauge in the truck shows 250 my scan tool was showing 248. I have done my absolute best to bleed air from the lines and all that jazz. Outside of Jfmorris idea of being sure I have an oil cooler on it, I don't have a clue what the issue could be. I need all the help I can get on this, I have a planned trip coming up next month and I'd like to hit the road with confidence. So with that being said, any assistance would be greatly appreciated.

jfmorris

I was talking about an engine oil cooler, which is a separate thing from a transmission fluid/oil cooler. The transmission fluid cooler is typical integrated into the radiator. An oil cooler for the engine oil is usually mounted in front of the radiator and AC condenser. Some year models also have a power steering pump cooler in front of the AC condenser as well.

All that said, I think it is new information (at least to me) that it gets hot sitting at idle. That would seem to exclude towing as a factor, and point to something more basic. I just don't know what.

I am over at Rockauto.com, with your 2004 Silverado 2500 6.0L pulled up, and under Engine, I see they sell GM genuine oil cooler lines for the ENGINE section of the parts list:

https://www.rockauto.com/en/catalog/...oler+line,5516

They also sell GM genuine TRANSMISSION cooler lines, in both upper and lower versions, in the TRANSMISSION section of the pats list, and they look much different than the engine oil cooler lines:

https://www.rockauto.com/en/catalog/...ler+line,10343

To me, that implies that there SHOULD be a separate engine oil cooler, with lines running from the engine to it. This would be distinct from the transmission cooler. If you don't have this, it can be added, and it would cool the engine oil. If you do have it, maybe it's not working right. Or the oil is not circulating properly and getting cooled as much as it should.

NOW, if you have 6 lines going to the radiator - i.e. the upper/lower radiator hoses, AND two metal lines from the transmission, AND two metal lines from the engine block, then its integral with your radiator, and you have it. On my 1996 C1500 and 2006 Silverado 1500, I only have the two lines from the transmission to the radiator.

Other than that, I am out of ideas.

Rednucleus

Just a huge long shot idea here - somewhere in the cobwebs ofmy old brain I remember a similar topic that ended up having a water pump going the wrong direction and so colled poorly. Seems to me there were two pump versions for the same model, and I have no idea how you can tell the difference. Bellieve it was a GM problem, either a chevy or a boat motor.
BTW my 93 Sub 5.7 has two trans cooler lines and two oil cooler lines that hook to the radiator.