Duramax Engine Oil Cooler

[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?

[Stlheadake]

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

I don't know and would be interested, but what I really want to know, is how many out there HAVE a guage for engine oil temp? I never thought of putting one on my liquid cooled engine. I routinely put them on my Dirt Bike (which is also liquid cooled), or air cooled riding mower.

hmmm? Now I have to get another A-pillar cluster and guage....I need a doctor's note, my wife won't argue with a doctor's note...

Calling Dr. Kennedy...

[Hubert]

Don't know about synthetic. Of course they can tolerate higher temps but that doesn't mean its ok for the engine to be hotter see below.

For dino oil the higher the temp the shorter the life expectancy and it varies depending on where you read.

For avg oil pan....
Some like no more than 180~190F which is what I have kind of settled on as its close to coolant temperature and thus is helping cool the engine more. Others say higher is ok. I'll say above 220F is getting hot and shortens life some. The hotter it gets it gets exponential. Say at 260F it should be changed at maybe 1/2 maintenance schedule time.


Of course its engine dependant oil sump size and some other little things but
Kubota says 240F continuous is max and intermittent max is 266F for avg oil temp measured in middle of sump. If above it indicates engine is overloaded. As in probable the piston is really hot from high EGT and heating the oil up.

[HH]

For avg oil pan....
Some like no more than 180~190F which is what I have kind of settled on as its close to coolant temperature and thus is helping cool the engine more. Others say higher is ok.

I know I asked, but I seriously doubt that 180 - 190 would be the limit as the oil is subjected to much higher temperatures being close to the combustion.

After posting, I read the second part of the above mentioned article and he states something like 360 as max temperature. So where is it measured, and anyone have an idea if this is a good number?

I have an engine oil temp gauge and it runs around 220 - 230F unloaded and near 270 - 280F pulling a trailer. I am running 15W-40 synthetic and measuring the temperature right before it goes to the cooler. I am using a tube and fin cooler.