e63 M6 buzz from engine

[Irish_Stu]

Noticed a sort of "buzzing" noise coming from the engine bay yesterday at certain revs. Anyone have any experience of the noise the vanos units make when they are on their way out?

Stu

[Schermerhorn]

Is an engine management light on?

Mine did it last year and it turned out to be VANOS pipe and valve. All done under warranty but car off road for two weeks.

Or it could be the throttle actuators/bodies. A common issue but expensive to put right. If it is under warranty it will be no problem.

[Schermerhorn]

Oh.....check your power steering fluid too. Mine was underfilled by dealers and made a groaning sound until I topped it back up. Perfect ever since.

CHF11S is what you need.

[Irish_Stu]

No EML. Just a metallic, raspy, buzzing noise at certain revs. Sounds like its coming from behind the dashboard, hard to pinpoint.

Car is under the full Mondial warranty so not too worried at the minute...

[Schermerhorn]

Hm. Wierd.

Are you on m5board.com?

[Hedgeman]

Try turning the aircon/blower/heater everything off. It sounds very similar to what my old M5 did on the odd occasion.

[Broadoakboy]

That is your VANOS system, sometimes low oil or an oil change can stop the buzz.

Next time it does it, pop the bonnet, it should be coming from underneath one (or both) of the black plastics caps at the front of each bank. May need some one to rev it gently whilst you're listening/watching.

Mine did it, I was getting the rod bearings changed anyway so left it, then forgot about it. It hasn't done it since after the bearing work.

[Broadoakboy]

That is your VANOS system, sometimes low oil or an oil change can stop the buzz.

Next time it does it, pop the bonnet, it should be coming from underneath one (or both) of the black plastics caps at the front of each bank. May need some one to rev it gently whilst you're listening/watching.

Mine did it, I was getting the rod bearings changed anyway so left it, then forgot about it. It hasn't done it since after the bearing work.