Will high oil temps in a direct injection engine help reduce fuel dilution in the oil by driving off or vaporizing some of the fuel? I'm asking in reference to a BMW twin turbo di engine, the N54, which in normal ops runs oil temp at around 250 degrees F.
Fuel dilution (di) and oil temps
- Thread starter m6pwr
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I don't think 250 degrees would vaporize anything but water. Diesel fuel is fairly stable and cools injectors, pumps, as well as burns very nice when the pressure reaches the correct number.
I perhaps should have mentioned that the N54 is a gasoline engine, which doesn't tolerate fuel dilution as much as a diesel.
Gasolines flashpoint is lower than diesel and some of the professionals will need to chime in on whether gas engines oil can reach the temp to flash off the gas in oil.
JHZR2
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We know the N54. I have an N55. Look at my FF UOA at only 1400 or so miles. High fuel though most all of those are highway miles. My 135i is >240F oil temperature when the engine is up to temp.
I'm just wondering if there is a sound engineering reason for BMW running oil temps at around 250 F in a di motor, or whether it just turns out that way because of the turbos.
I would bet it's related more to the engine bay being full of heat-producing items. 
My Audi suffers a similar problem. Small car with massive engine (not DI). Oil temps get north of 220.
My Audi suffers a similar problem. Small car with massive engine (not DI). Oil temps get north of 220.
It has a great deal to do with the specific power output, driving style, and basic design.
The BMW turbo motors (and many others) have piston oil squirters, which spray directly underneath the tops of the pistons.
It's a great durability feature and it will definitely heat up your oil!
The BMW turbo motors (and many others) have piston oil squirters, which spray directly underneath the tops of the pistons.
It's a great durability feature and it will definitely heat up your oil!
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