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View Full Version : Z4 3.0i - Whistling Sound


keepark
02-04-2009, 12:03 AM
Hi guys,

I have this whistling noise when 1,000~2,000 rpm.
I hear no whistle when it's idling, but when i gently press on the gas pedal, it makes the whistle and the engine revs right after.
I hear it the most when I'm driving in the parking lot, rpm around 2,000 it makes the sound and when it revs up, it disappears. Only whistles on low rpms.

I've already changed the oil separator, and i don't know what else to do.

Any ideas?

dbworld4k
02-05-2009, 12:37 PM
Alternator pulley?

Blades
02-05-2009, 12:51 PM
Alternator pulley?

that or the alternator itself .. I get a small whistle on really cold days.

Nick_ll
02-07-2009, 09:36 PM
Very small whistle at those RPM could be related to idle control valve and the vacuum lines around it. It could be making such a noise when the valve is partly closed maybe?

keepark
02-07-2009, 10:57 PM
Very small whistle at those RPM could be related to idle control valve and the vacuum lines around it. It could be making such a noise when the valve is partly closed maybe?

This sounds very interesting. I have noticed a slight but constant movement of the rpm gauge when idling.

Where is this valve/hoses?
If you could identify them from a diagram below, i'd really appreciate it

http://www.realoem.com/bmw/partgrp.do?model=BT53&mospid=47799&hg=11&fg=05

Nick_ll
02-08-2009, 12:15 AM
Part #8 on this diagram.
http://www.realoem.com/bmw/showparts.do?model=BT53&mospid=47799&btnr=11_2879&hg=11&fg=40
As far as I know, this valve generally doesn't fail, it gets dirty and you can clean it up with throttle body cleaner.
I would however doubt it and look more towards the vacuum lines that get to/from it.

keepark
02-08-2009, 12:54 AM
Part #8 on this diagram.
http://www.realoem.com/bmw/showparts.do?model=BT53&mospid=47799&btnr=11_2879&hg=11&fg=40
As far as I know, this valve generally doesn't fail, it gets dirty and you can clean it up with throttle body cleaner.
I would however doubt it and look more towards the vacuum lines that get to/from it.

I tried to identify the location, it seems like the sound is coming from this unit. I'm not sure if it's the unit that's failing or the connections around it. I'll take it apart and clean it up to see if it works.

Thanks again. I'll post an update right after.

keepark
02-08-2009, 12:57 AM
BTW. it's not the intake boot.

rodo
02-10-2009, 11:38 PM
lol. I was gonna say that's your intake doing its job

keepark
02-10-2009, 11:39 PM
It could be the alternator pulley........................cuz the sound seems to come from way front of the bumper.
Easy fix?