Duramax Engine Oil Cooler

[Stlheadake]

I just read an article in MaxxTorque regarding cooling the engine oil. This makes much sense to me. What I read was the first of a two part article, and part one laid out the research for utilizing a separate cooler.

Now in all honesty, I don't normally read this magazine, so I am not really familiar with the author but his research SOUNDS pretty good. His assertion is that engine oil does double duty of lubrication AND cooling, AND that the oil to water cooler is pretty inefficient.

This is only part one which basically explained the problem, and I assume that the second installment will give solutions. The problem is that I can't wait for the second installment.

Anyone have any experience here? Mark do you run a separate oil cooler? John is an extra oil cooler worth it as far as extending engine life, and possibly gaining power (cooler oil=cooler engine temps)?

Is this just hype or is there more to it?

[More Power]

When a question like this arises, I usually ask whether the author is in the business of selling parts that offer a solution... This is one reason why The Diesel Page doesn't sell anything that you can use in or bolt onto your engine/truck.

If there was a persistent need for a "solution" to a problem with the Duramax (like the FSD/PMD 6.5 issue), we'd see the problem show up frequently in the Duramax forum and I'd get at least a few questions/discussions about that problem every month. We/I don't.... I've probably discussed the oil cooling/overheating topic in an email or phone only a couple of times in the past 7 years.

Jim

[Mountainman]

Sounds like "KillerBee" to me! This was a gigantic "can of worms" in another forum where he was eventually kicked off! IIRC, KB was an airline pilot, not an engineer. FWIW, go carefully here cuz there is another solution to the overheating problem that brings down coolant temp AND oil temp that does work! If you don't tow heavy and you don't have OH, why bother. Jim B

[Stlheadake]

I haven't read the entire article yet. This was part one of two..? Basically he was pointing the 'heat' problem at what causes the fan clutch to kick in while towing. His assertion was that this is at least in part caused by excessive heat, and he pointed to engine oil.

Here is the link to the article if you care to have a look: http://www.maxxtorque.com/excerpts/3...oling-part-one

I just finished reading part two, and though he continues to make the case for better oil cooling system, he leaves it at that. Just that the cooling system of the DMax is already fairly challenged (though seemingly sufficient) but by cooling the engine oil directly, the entire engine benefits.

Frankly, I don't really know where I could/would mount an oil cooler. The front clip is at capacity pretty much already. I would think sticking another radiator in front of the other two radiators would only compound the problem.

I was 'fishing' for your thoughts here. I seem to have gotten them. I do tow heavy when I tow, which is only about twice a month on average, and usually only for around a hundred miles each way. Though I live in the mid-west, and summers can be pretty hot, I'm not towing through Death Valley or anything.

Like I said before, I value the info here, and this was another magazine/website related to GM diesels that I found. I don't know much about it other than that.

[JohnC]

Oil to water coolers are not uncommon and for their size very efficient. I don't see how it much matters if you're asking the radiator to shed the heat directly or putting an oil to air cooler in front of the radiator and asking the radiator to make do with hotter air but less heat.

An advantage of the oil to water cooler is much more stable oil temps, albiet sometimes higher temps.

[Stlheadake]

Thanks Jim. I am not going to race out and get one just yet, but I wondered if they had been discussed or what others thought. I suppose you really can't go wrong with 'extra' cooling.

[Hubert]

I liked the articles and sounded pretty good to me. And think it would help the 6.5 as its been reported to have high oil temps. I like your concern on just moving thermo load on the stack no huge benefit in keeping it in the stack but if you add capacity by taking it out to stack then much more cooling.

I agree with John that the radiator/oil cooler helps stabilize the oil temp as the radiator is somewhat kind of sorta thermostatically controlled. Or could heat the oil when coolant starts to circulate. An external oil cooler is not usually really thermostatically controlled.

I'd like to comment more later gotta go.

[More Power]

In the Duramax, the engine oil cooler (stacked plate type) is inline right after the water pump. So, coolant is continuously passing through the oil cooler whenever the engine is running. It's not like a in-rad oil cooler, which sees coolant flow only when the t-stat(s) are open.

The Duramax/Allison equipped trucks do have an in-rad ATF cooler, which resides on the cool side of the radiator, and just upstream from the water pump.

For most Duramax owners, all this is much ado about nothing....

Jim

[Hubert]

Thanks Jim - Uhh I had forgotten a few details. But I think my points should still be valid.

Along the lines JohnC commented on - the coolant cooled oil cooler will still will warm the oil if the coolant is warm and or won't cool it too much if coolant is warm. Where as an external air - oil coolers may not be thermostatically controlled and cooler climate could cool oil too much. I don't remember this point in the articles but its been awhile.

And 2nd point is if the oil cooler is just moved to front of stack then gain is questionable but if sized correctly and placed correctly then cooling capacity is increased.

I agreed in basics of article oil does a fair bit of cooling on modern diesels (ones with piston sprayer's). And oil temperature is fairly important on Diesels under significant load. As oil is what cools the piston (along with intake air). Coolant only cools the head(s) and block it does not cool the piston directly and the piston sees high temps under load.

When I get a chance I'll reread article and try again with clearer post.

With adequate block and head cooling the circulating oil will transfer heat from piston to block and onto coolant. But when coolant is hot and thus the block the oil doesn't shed the heat as well is a different wording.

Normal loads this is not a problem approach more than 85% continous engine load and it is an issue with continuous oil temperature.

[HH]

Since we are on the subject, what is the highest recommend temperature for synthetic oil and dino oil in an engine?