Can take oil cap off while running and noise stops, could this be a pcv valve. Have checked idlers and all belts.
BMW Q&AAsk Your Question
1998 BMW 740iL Question: Whining noise in engine.
Answer #1Bret Bodas from RepairPal Test Shop, June 13, 2010, 10:21Master
It appears to be a pressure issue inside the crankcase. Check for vacuum leaks and if it has a pcv valve, replace it.
Dont Hate December 11, 2010, 20:55Rookie
I have the same problem , weird., i dont know why? remove the dip stick and the whinning , spaceship sound will end...replace it, whining sound is even loader. Help us , who really need..
ReplyVisitor, December 12, 2010, 12:19
I finally took it in and they replaced the intake gaskets and the noise and running rough stopped. Been running great since.