Vapor fumes from oil cap opening

[Jarpin]

Is it a somewhat trusted indicator of oil burning if these vapor fumes are visible when a car's engine is hot and just turned off, or is it normal in most cars over 200k miles?

 

[K.Aoi]

Is it a somewhat trusted indicator of oil burning if these vapor fumes are visible when a car's engine is hot and just turned off, or is it normal in most cars over 200k miles?

I've seen this on *NEW* engines just after shut down. Completely normal.

 

[aquariuscsm]

Completely normal.

 

[ZeeOSix]

Check to make sure the PCV system and valve is in good shape.

 

[Accent Abuser]

Is it a somewhat trusted indicator of oil burning if these vapor fumes are visible when a car's engine is hot and just turned off, or is it normal in most cars over 200k miles?

Normal. My car has done this since new and doesn't burn a drop of oil. Oil get very hot when the engine is running and even without water condensation can vaporize.

 

[K.Aoi]

Normal. My car has done this since new and doesn't burn a drop of oil. Oil get very hot when the engine is running and even without water condensation can vaporize.

To add to this remember that the inside of an engine is a harsh place, if it's OHC there's camshafts spinning at thousands of RPM flinging oil all over the place, the crankshaft and connecting rods along with piston oil squirters... Timing chains... Combined with the heat its totally expected that all that oil being flung around vaporizes.

 

[Accent Abuser]

To add to this remember that the inside of an engine is a harsh place, if it's OHC there's camshafts spinning at thousands of RPM flinging oil all over the place, the crankshaft and connecting rods along with piston oil squirters... Timing chains... Combined with the heat its totally expected that all that oil being flung around vaporizes.

Yeah that too. If one were to open the oil cap on a DOHC timing chain engine while it were running they'd be sprayed with oil.

 

[wpod]

Blow by.

 

[Johnmpb]

Most likely blow by as previously stated. Might be some burning as well. All engines burn oil

 

[Jarpin]

Thanks for all replies. That makes me feel a little better.

 

[Jetronic]

Is it a somewhat trusted indicator of oil burning if these vapor fumes are visible when a car's engine is hot and just turned off, or is it normal in most cars over 200k miles?

It's very normal, and it's likely water vapor at it's core.

 

[High Performance Lubricants]

Normal. My car has done this since new and doesn't burn a drop of oil. Oil get very hot when the engine is running and even without water condensation can vaporize.

You are not seeing oil vaporize. You are seeing moisture leaving the oil. Even when running flash tests at which point the oil vaporizes enough only to flash, you don’t see anything coming off the apparatus. If you are chasing fire point or auto ignition you will be at a level where the oil will smoke. These are temperatures you will never see in an engine.

 

[Slow Car Sport Mode]

Thanks for all replies. That makes me feel a little better.

Clean or replace your PCV valve and re-assess.

 

[DGXR]

When the hot gases from the crankcase hit colder ambient air, condensation may form instantly and looks like steam/vapor coming from the opening. This is mostly likely what you are seeing. A tiny bit of water vapor (humidity) in the crankcase is inevitable because the combustion process produces water and piston rings do not seal perfectly.

 

[DavidJones]

Based on all the replies above, you should rotate your tires.

 

[demarpaint]

As already mentioned it's condensation or moisture boiling off, its normal and in the winter you might see it even more.