Engine Oil Vapor

[modularv8]

When I open my oil filler cap after reaching engine operating temperature (engine turned off), there are oil vapors rising up through the filler tube. The vapor appears to be white and whispy, kind of like the smoke that comes off a cigarette. Engine oil temperature rarely gets over 200F. Anyway, it was worse with Motorcraft 5w20. Less with Quaker State Synthetic 5w20 and nearly gone with Pennzoil Platinum 5w30. Anyone experience this with their vehicle? Is this common? Is this a fine oil mist from hot oil churning in the engine, oil volatiles, or a mixture of oil/water from combustion? Any ideas.

 

[MrMeeks]

Do you see water/oil mix on the dipstick?

 

[modularv8]

No, everything is normal. It isn't a problem, just wondering if it is an indicator of the quality of the oil.

 

[aquariuscsm]

I wonder if thinner oils are more prone to burnoff in a hot running engine?

 

[NateDN10]

I've had this happen after the engine's up to temp (after a ~20 minute drive) and I've taken off the filler cap. I've seen it with both Mobil 1 0w30 and Castrol Edge 5w30. I was wondering about it, too, since my car only burns a few ounces over 8-9000 miles.

 

[uart]

While the engine is running the crankcase is constantly getting a small amount of "blow by" vapours (and the oil is getting a small amount of fuel dilution which also comes off as a vapour once the oil is at full temperature). When you take off the filler cap from a warm engine you're just seeing these normal crankcase vapours.

 

[mechtech2]

modular -
It's everything that you mentioned, and probably more.
This normally is sucked through the PCV system to the intake manifold [while running].
It is also why I use a catch can in my PCV system.