[Nfsplayer]

Hello

today when i was driving i heard whistling noise coming from engine. It usually start's when RMP get's over 2. Sound's like it coming from alternator. What could it be? it's 2001 bmw 325i.

 

[rkcampbell]

Do you have a cold air intake by any chance? I have a Dinan CAI and mine squeals around 1900 rpm.

 

[Numark318i]

Check vacuum lines, the snugness of your air filter box (does it seal) and also check the bearings in your belts tensioner.

That is what made the noise in my 330. Replaced both tensioners and no more noise.