My 1997 840ci has a rather annoying and loud whistling sound upon start up. It mostly goes away after driving or 30 minutes or so. Any idea the issue?
The link below is my youtube page with a 20 second clip of the engine.
Thanks for any assistance!
https://youtu.be/fAoiRraizR0
I anticipate it is a vacuum Leak.
The many profile gaskets around the M62 engine get brittle with age and can leak very badly.
I would suggest you first test the crankcase pressure regulator by lifting the oil filler cap ever so slightly to let air into the crankcase while the engine is idling. If the cap is hard to lift and you get a big whoosh of air being sucked in, CCPR has failed.
Next, take a can if Dust Off and place a small diameter hose, 2-3 ft long, over the pin nozzle. Then use the free end of the hose to direct the inert gas around the intake gaskets while the engine is idling. At an intake leak the engine RPM and idle smoothness will change. You can repeat the introduction of the gas at a leak to confirm the change in idle smoothness and RPMs.
Wow. THANKS for the info! I'll try that, today.
It's easy to tell if that is the PCV whistling away - the noise will immediately go away if you partially lift the oil-filler cap. If the noise doesn't go away then it isn't a vacuum problem.
If the noise does change then the PCV is the problem - and you might as well sort out all the other vacuum leaks at the same time:
https://www.meeknet.co.uk/e31/BMW_M6...cuum_Leaks.htm
Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i
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