Motor Oils Cool Your Engine

Not the big end rod and crankshaft journal bearings. The rods are too long to transfer much if any heat from combustion into the rod bearings. All the heat generated in the rod big end and crankshaft journal bearings is simply from the oil shearing in the hydrodynamic wedge.



I'd like to see test data from those experiments ... would be interesting, and I'd venture to say the oil would heat up more than most would think just from the friction and oil shearing from the engine "running" without combustion.


You will have to wait until his next reincarnation before you see any test data.
 
I always pause when I read folks suggesting to buy a Redline 20 because it’s almost as thick as a 30 …
If I was sitting on that fence … think I’d just head for Walmart and pick a Dexos 5w30 synthesized oil …
Yeah I find them absolutely interchangeable in my vehicles.
 
Ive always been taught oil was primarily cooling, and everything else secondarily, but Im old...

On a high perf marine engine you never exhaust the cool water and only have to back out of it for control reasons or escalating oil temps.

Ive seen oil skyrocket from 180 to over 300 in minutes while the water temp stays at 100 degrees.
On the Oldsmobile engine in my boat, I used the oil pressure as a go indicator. To fast for too long and the oil pressure would drop. I would then back out of it. A lot of people never looked at the guage, and got to buy new engines.
 
No engine has 100% cooling provided by the circulation of engine oil. Every engine has either a liquid or air cooling design. Liquid cooled engines usually have some air cooling as well.
The oil is generally cooled by indirect air cooling. The oil pan is a big oil cooler. In the olden days, the oil pans were often finned to accomodate better cooling, and inline with airflow under the car.
 
Speaking of oil cooling engines, I noticed higher coolant temps with M1 5w30 EP HM than with M1 Euro 0w40!
 
Speaking of oil cooling engines, I noticed higher coolant temps with M1 5w30 EP HM than with M1 Euro 0w40!
In which of your cars?

Honest question: how are you reading that temperature? Because if it's your dash gauge, those are compensated to remain in the middle.

And if you were measuring in the past few months, well...
 
In which of your cars?

Honest question: how are you reading that temperature? Because if it's your dash gauge, those are compensated to remain in the middle.

And if you were measuring in the past few months, well...
In the maxima 09. I use OBD live readings all the time. My average with 0w40 was 192F. Now at 196F to 198F. Oil temp stayed 203 to 208 in both oils. Plus weather was hotter in the past few weeks.
 
In the maxima 09. I use OBD live readings all the time. My average with 0w40 was 192F. Now at 196F to 198F. Oil temp stayed 203 to 208 in both oils. Plus weather was hotter in the past few weeks.
These are good readings but you need to also compare the ambient, coolant and IATs temperatures respectively to know what is going on.
 
The Gen 5 Chevy LS engines have oil jets that spray the underside of the pistons.

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In the maxima 09. I use OBD live readings all the time. My average with 0w40 was 192F. Now at 196F to 198F. Oil temp stayed 203 to 208 in both oils. Plus weather was hotter in the past few weeks.
Again I wonder how the oil somehow affected the thermostat control temperature.
 
In the maxima 09. I use OBD live readings all the time. My average with 0w40 was 192F. Now at 196F to 198F. Oil temp stayed 203 to 208 in both oils. Plus weather was hotter in the past few weeks.
If there was no real difference in oil temperature then something else must be effecting coolant temps. This car has an old fashioned mechanical thermostat I take it, or is it computer controlled? If your coolant temp went up with hotter weather you might want to ensure the radiator is clean and not partially clogged from road debris.

Only way to get a good temp measurement for comparisons on anything on an engine is to cruise at the same speed and RPM for miles on the freeway at same ambient temp as that's the easiest use condition to repeat.
 
If there was no real difference in oil temperature then something else must be effecting coolant temps. This car has an old fashioned mechanical thermostat I take it, or is it computer controlled? If your coolant temp went up with hotter weather you might want to ensure the radiator is clean and not partially clogged from road debris.

Only way to get a good temp measurement for comparisons on anything on an engine is to cruise at the same speed and RPM for miles on the freeway at same ambient temp as that's the easiest use condition to repeat.
I have no problem and I'm not investigating anything. It is just an observation. Basically all other parameters were equal except the oil type.
 
I have no problem and I'm not investigating anything. It is just an observation. Basically all other parameters were equal except the oil type.
Well, the oil temperature only varied in a 5F range (203-208F), as did the coolant temperature (192-198F) ... so what might be thought of as a "correlation" effect of the oil used may just be in the noise level of measurements due to the conditions the measurements were taken.

Did you take these measurements under the same exact use conditions on the same exact day after everything was at a stead-state temperature condition?
 
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I have had this discussion/argument over decades with mechanics and car enthusiasts.
What I learned, many years ago, in Cat Engine diesel school was an oils properties (in order):
1. Cool engine parts
2. Lubricate
3. Keep the engine clean and free of contaminates
We were taught the same when I was trained on the F-16 in the Air Force.
Thank you for your service
 
I didn't read through all the responses, but did someone touch on the subject of oil coolers? I have one from factory on my crown vic, but if you really wanted to, shouldn't we install oil coolers on our cars?
 
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