weird noise coming from front of the car

[BNK]

I've noticed a low-level squealing like noise. The noise is most apparent when the car is stopped,or when just starting to move....It's easiest to hear when you apply light throttle, because as the rpm's rise, i'm guessing the engine noise drowns out the squeal. When i start the car, the sound is not there. It takes about 20 minutes of driving at a decent pace to get it to start. I replaced the Vanos Unit and the noise is still there. Does anyone have an idea what could be making this noise?

Thanks

BNK

[hal9000]

Is the AC on? Maybe compressor?

[BNK]

i found out what was causing the noise, i need a new Alternator

thanks anyways

BNK

[RidinLow]

I think I have the same problem... under light throttle, it sounds just like a faint squeaky brake pad. I took it to the dealer and they said it was a loose heatshield, but the noise is still there.

Can you give any more details on your diagnosis?

[Loud_TIGER]

crap i think i'm getting the sound too... is it common for alternators to fail

[Stinky]

I've had that noise for awhile. I thought it was the Primary tensioner and changed it but it's still there. Listened more carefully and it sounded like it was coming from the alternator. I also noticed when I would turn on my headlights it would get louder.
So I got my new alternator, just need to put it in.

By the way, is $224.60 w/ $30 core charge a good price for an 80A Bosch?

[Blazin95Red325i]

did you guys try changing the voltage regulator first?

[indicaM3]

rear/front main seals and oil/vapor separator can make high pitched squeek/whistle/squeal noises too. im in the middle of this right now.

[M3Nut]

BNK- How did you conclude it was the alternator? Did you remove the belts and spin it?

The bmw mechanic called it a symptom of "dry belt" (huh?) where the belt is slightly slipping. The sound isn't apparent at the very start of the morning drive, but after it has warmed up a bit I hear that slight squeeking noise at idle. It's ANNOYING AS HELL.

The tensioners, idle pulleys and belts were replaced less than a year ago so I think I can eliminate those. I'd like to hear other's opinions.