I recently decided to check the mass air flow sensor on my BMW 525 e34 m50 engine..I found it to have oil residue in it..then I found oil in the rubber boot that is between the Maf and throttle. What is this and is it normal??
Oil getting into the intake boot is not normal. You need to have the PCV system checked to see if it is plugged and excessive combustion pressure is building up in the engine causing it to push oil into the intake system. You may just need to replace the air filter and the PCV valve.
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