Engine Oil Cooler effectiveness

Engine oil cooler is a Heat exchanger and the oil is "cooled" with the coolant when the oil gets hot and the heat exchanger also helps heat up the oil at cold temperature starts. The sticker also calls it "Engine oil cooler".

2019 and up models have ATF "cooler" (previously called warmer) which is also a Heat exchanger.
2018 and older models have the real cooler (air cooled).

based on members observations , the effectiveness of the 2019 and later model ATF "cooler" (heat exchanger) is in question and the heat exchanger is not very effective or is not as effective as the air cooled models ...

my question is how effective do you think the engine oil cooler is since it is also a Heat exchanger. I am not sure about the size difference between the 2 heat exchangers but has anyone made any real temperature measurements?

 

Great question, my 2021 Tundra coolant temps are always 195F. When I had a F250 with oil temp gauge after everything was steady state oil temps were always within 10 degrees of water temp. So oil temps dont appear to be an issue IMO.

 

I am very surprised that Tundra doesn't have an engine oil temperature sensor like most other trucks or F250!
Some obdii gadgets display the calculated/estimated oil temperature but there is no real sensors like ATF.

 

My uninformed opinion is that it would be like atf torque converter to pan temps. The oil might spike while the coolant stays about the same, but it comes back down quick when rpms lower.

Side note, is there a power steering temp gauge? It also has a cooler.

 

Where is the power steering cooler located? I guess I can go to the car and follow the lines ... Is it in front of the coolant radiator?

 

You talking btu’s of cooling?

Best way would be to measure the engine coolant flow rate and measure the input temperature and output temperatures. Could then directly calculate the cooling.

Another way would be to let the truck warm up sitting still and watch the temperatures. Normally the trans temperature lags behind the water temperature by 40-50 degrees. If the water temperature is changing would make the math hard.

so let the engine idle until it gets to operating temperature. Then time how long it takes the oil to raise each degree. Would need to then estimate the thermal mass of the transmission (oil + metal). Then do some calculations to find out how much warming it does per temperature delta (oil - water)

 

Another easier method.
Find a long uphill grade. Stop at the bottom and note and the transmission temperature, for this test is better cold under 130 degrees or so. Start a timer and go up the hill in s3. Stop at the top a Measure the new temperature and the time.

next day
Run the engine with in park keeping the rpms around 2k. Time how long it takes for transmission to go from the low temp to the high temp measured the day before.

Then divide the times to get the heating/cooling ratio where 1/1 is optimal. 1/2 means you have half the Cooling capacity need etc

Make sure to use pan temperatures.

 

A liquid to liquid exchange is more effective than a liquid to air one. This is nothing new. My 2001 4runner has the same setup. It works, 327k+ trouble free miles....

 

The PS cooler is that finned pipe in the grille area below, and in front of, the radiator and AC condenser.

 

Intuitively, not very effective as a "cooler". The reason it's not very effective is the same as why the so-called transmission "cooler" is not effective. Neither "cooler" has enough heat transfer area to cool one fluid (oil) with another (coolant) that has nearly the same temperature. If the Delta T is low, the transfer area has to be large, and it's not.

For the air to ATF cooler, the Delta T is large, and the surface area is moderately large as well, so it does a great job when used for the ATF.




Overall heat transfer coefficient, U, is a combination of the heat transfer coefficient of the fluids, and the heat conductivity of the heat exchanger material, i.e. brass, aluminum great for heat transfer, glass not so much.

https://www.engineersedge.com/heat_transfer/overall_heat_transfer_co.htm

 

Oh my God! You mean we have to worry about the engine oil overheating now as well as the ATF? WTF Toyota? My truck is going to explode at any moment! What in the world am I going to do?

 

This is true, but both fluids are hot.
While towing a 5500 pound trailer down a highway the engine is 195F and the trans is 217F (both pan and torque converter).

As you drive the torque converter will unlock (torque converter temps are 25 degrees higher than pan temps when unlocked) and apply more heat. The pan temp eventually climbs to 230 degrees and finds a happy place. If tq unlocked will go higher but will go back to 230 when locked.

If go over a mountain where needed to hold the tq unlocked for 20 minutes think would get to that 300 max temp quickly (i was to scared to try in so installed a cooler).

 

ON THE OTHER HAND...You do not want an engine oil cooler that does a super great job and cools your oil temperature below coolant temperature. That can result in different rates of expansion between cylinder case and moving parts, increased wear, and other bad things.

During the transmission cooler threads, I asked one 2020 owner what he was observing for engine oil temperature while towing heavy. He said he observed abot 225 degrees, but of course he had the tow package and the engine oil cooler, sans auxiliary transmission cooler.

 

No, we have a pressure gauge though. I replaced my ps cooler but did not record temp differences. I’m going to step up to a bigger one, will document the change, but will be useless vs stock.

 

Oil temp is inferred, so nobody actually knows. Suspect it is a non issue. From what I can see looking through various year calibrations, ECT over 176F and everything is good, under, and flirting with that temp would be bad.

 

engine oil cooler is a bit bigger than the transmission cooler. However the engine oil cooler does have a finned set up. This adds surface area.

The coolant that routes to the oil cooler comes off of a different path of the coolant flow and is likely much cooler than the coolant that flows through the transmission cooler. So the engine oil cooler has more temp difference and more surface area.

The existing transmission cooler doesn't really cool until the temp difference between atf and engine coolant get higher and higher above 195F.

Another aspect of the engine cooler is it is cooling 8.5 qts instead of 14 or so.

 

He was talking about engine oil temp and cooler, not transmission fluid temps.

 

Man you guys love beating a dead horse

 

The future plan is to now start a whole new series of engine oil cooler threads with uninformed opinions, speculation, and mindless bs. Giddyup.

 

Stick to what you're good at.

 

This is the first thread I’ve seen recently about engine oil temps.

 

Another cooler thread with everybody up in arms bc there’s not a visible cooler like their last truck had.. oems have been using liquid to liquid coolers forever and they work

 

If anyone reads this board long enough they’ll be too scared to even take their truck out of the driveway

 

I don’t think that’s what the OP said at all. The engine oil cooler is visible and has not changed. Also, reread post #10 regarding the liquid to liquid cooler.

You can also read other posts on here about how 19+ owners are seeing 50f+ higher temps with in the atf only their liquid to liquid cooler.

 

I'm still trying to find my diff cooler and windshield washer fluid cooler. Feeling like toyota really dropped the ball on these key features.

 

I just checked, you’re right, there is no diff cooler or windshield washer fluid cooler. I investigated further and discovered there’s also no hub cooler, no u-joint cooler, and no headlight cooler! WTF Toyota!!!!!!!!!!

 

^This^

FYI
I searched before posting and did not find any Engine Oil cooler threads discussing the effectiveness of it.

since everyone is concerned about the effectiveness of the new ATF "cooler" which is a Heat exchanger ... It made me wonder about the Engine Oil cooler which is also a heat exchanger.

Next time I'll start a mpg thread