Motor Oils Cool Your Engine

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Dec 26, 2005
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Yes, and the main reason a +/- 2.5F change is basically noise.
The biggest nonsense here is trying to use coolant temperature to gauge oil temperature, you're a whole order of magnitude and an entire system away. At least try and make the argument you're monitoring oil temperature and not coolant.

But better than your perception of cooling fan cycling rate I guess :rolleyes:
 
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Wouldn't thicker motor oil get hotter more from pumping losses (the oil pump has to work harder to push it through the filter & bearings), more from friction in the bearings, and make the engine work harder as it does so? That's the whole concept behind CAFE driven viscosity decreases, to try to minimize friction (for some incremental MPG gains). I'm sure straight 40 or 50 takes a lot more energy than 0W-8...
 

ZeeOSix

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Wouldn't thicker motor oil get hotter more from pumping losses (the oil pump has to work harder to push it through the filter & bearings), more from friction in the bearings, and make the engine work harder as it does so? That's the whole concept behind CAFE driven viscosity decreases, to try to minimize friction (for some incremental MPG gains). I'm sure straight 40 or 50 takes a lot more energy than 0W-8...
Yes, a thicker oil will heat more from shearing in the same exact use conditions. The difference in shearing friction becomes smaller the hotter the oil becomes, so part of saving fuel is also in the warm-up stage of the engine running when the oil goes from very thick to very thin, relatively speaking.
 
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Yes oil flow is critical to the internal oil cooling process. So thinner oils *can* cool better than thicker oils, which is the main reason why I am not a fan of going too thick (a little is ok IMO). But oil flow is not determined by viscosity alone... the type of oil pump, deposits & sludge, etc. all have an effect on oil flow.


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.
They all have a lot of air cooling. The air is what cools the coolant.
 
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The biggest nonsense here is trying to use coolant temperature to gauge oil temperature, you're a whole order of magnitude and an entire system away. At least try and make the argument you're monitoring oil temperature and not coolant.

But better than your perception of cooling fan cycling rate I guess :rolleyes:
So the Temp gauge in my GM 1500 is a Coolant sensor? Is the oil usually hotter or colder in proportion to the coolant temp? For instance, on short trips, the Temp reaches optimum temp relatively quickly, is the oil still heating up or does it heat up faster than the coolant temp reads?
 
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So the Temp gauge in my GM 1500 is a Coolant sensor? Is the oil usually hotter or colder in proportion to the coolant temp? For instance, on short trips, the Temp reaches optimum temp relatively quickly, is the oil still heating up or does it heat up faster than the coolant temp reads?

Coolant will heat up quicker. Oil will lag 5-10min.
But then at steady state oil should be hotter than coolant.
Coolant should usually be <200F, Oil should be 200-210F

This of course is weather, altitude, and load dependant.
 
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