W206 air coming out of oil cap/blow by?
10-21-2023, 10:36 PM
#1
Junior Member
Thread Starter
W206 air coming out of oil cap/blow by?
Hi forum,
Just did an oil change on my MY23 W206 C300, but I noticed that there is significant(probably not excessive) air flow coming out of the oil filling cap(when engine is idling, and with oil cap removed). The car has 5k miles.
It can be felt by hand and matches engine strokes. But when the oil cap is on it doesn't hiss or make air escaping sound.
I am not sure if it is normal on these cars since it's a turbo and much more modern than my other cars. Didn't notice this behavior on my W204 or 16 BMW X5 but they are not turbos.
It feels like a blow by which on old cars indicate bad piston ring, maybe this is how all new cars are?
Sorry for lack of audio/video, can't figure out how to visualize the issue.
Just did an oil change on my MY23 W206 C300, but I noticed that there is significant(probably not excessive) air flow coming out of the oil filling cap(when engine is idling, and with oil cap removed). The car has 5k miles.
It can be felt by hand and matches engine strokes. But when the oil cap is on it doesn't hiss or make air escaping sound.
I am not sure if it is normal on these cars since it's a turbo and much more modern than my other cars. Didn't notice this behavior on my W204 or 16 BMW X5 but they are not turbos.
It feels like a blow by which on old cars indicate bad piston ring, maybe this is how all new cars are?
Sorry for lack of audio/video, can't figure out how to visualize the issue.
10-24-2023, 06:05 PM
#2
Junior Member
It could be just air blown around by the moving parts. With a turbo you often have an arrangement of valves so that when the turbo is on and there is positive intake pressure a valve stops it from pressurising the head. Under idle with the cap removed you are probably not getting the very slight vacuum that your other cars have so you are noticing this.
