whistling noise coming from engine

[LoudBimmer]

Hello

today when i was driving i heard whistling noise coming from engine. It usually start's when RMP get's over 2000. Sound's like it coming from alternator. What could it be? it's 2001 bmw 325i.

[bassHZ]

alternator whine ? when ur rca's are close to ur power cables

[BulletInjection]

Could be that or your intake. When I rev mine up quick and let off my intake sounds like a blow off valve lol

[Loudcivic]

check for a vacuum leak. look for split or broken hoses around the top of the engine were the intake hooks up to the motor. a noise like that is usually a vacuum leak. possibly could be a bearing going bad to. take a video of it and put it up on youtube and post it here so we can hear the noise if possible

[LoudBimmer]

other thing is, when i start my car up it shake little bit. could that be connected to that noise in engine?

[Livin Loud 906]

If your car has a vacuum leak like Civic said that would contribute to a rough idle. So yeah it could all be related.

[Boon]

other thing is, when i start my car up it shake little bit. could that be connected to that noise in engine?

Either you've got a vacuum leak as mentioned, which is causing the whistle and the rough idle because the engine is running a bit lean (air bypassing the AFM/MAF or whatever those cars use) OR what you're hearing is actually a squealing from a shagged bearing and your engine is on the way out, which is why it's running rough.

Checked your oil level recently? When was the car last serviced?

[Gotloud555]

If you engine start to shake it could be a problem in general. I would start looking at the engine mount on each side, behind, and side to see any tear or crack..

[Mosin]

With vehicle idling take some starting fluid and spray it up and down the vacuum lines and if the idle changes at all, you've found your leak.