View Single Post
      02-13-2018, 08:00 AM   #10
Second Lieutenant
eyehategod's Avatar

Drives: 2012 335i Xdrive (E92)
Join Date: Jan 2018
Location: Washington D.C.

iTrader: (0)

Originally Posted by arkie6 View Post
The N55 and earlier N54 engines in the 335i do not have a MAF (Mass Air Flow) sensor. The N54 N55 have a MAP (Manifold Absolute Pressure) sensor. These sensors aren't generally as sensitive to oil in the intake tract as hot wire MAF sensors. Regardless of what sensor you have, changing your engine oil would have absolutely no effect on it. If you have an oiled gauze air filter like a K&N, putting too much oil on the air filter has been reported to contaminate MAF sensors on other vehicles. But this has nothing to do with changing your engine oil.

The carbon inside your cylinders is most likely from oil that has burned up during combustion leaving behind the carbon deposits. The most common source of this oil on our engines is the Positive Crankcase Ventilation (PCV) system that dumps crankcase oil vapor into the intake ports. This is why people install oil catch cans (OCC) on the PCV system.
Thanks for the info - I don't remember where I read that comment about oil from the filter housing getting onto the MAF sensor. I was wondering if an oil catch can would be worthwhile on my car, looks like I found the answer.