[Paykash]

So I have this weird noise that keeps coming on. It's a buzzing sound coming from somewhere in the engine bay.

The noise tends to come on once the car is warmed up. If I smash the gas to the floor it stops temporarily...I have also noticed that in the winter months it never came on, so heat seems to be an issue... the other thing is that it is intermittent.

I have taken it to 2 BMW dealers and a specialty shop and noone can get it to make the noise again. Even tho I've shown them videos of how it sounds, they haven't figured it out. The 1 shop looked at all the pulleys and belts and everything seemed to be fine.

video
https://photos.app.goo.gl/j9hKeR1ts7rYuqzc8

Any ideas???

[overcoil]

next time it happens, have a long stem screwdriver with you and carefully place the metal flat tip on the alternator and bring your ear to the handle end and listen. if it is the alternator there should be no doubt as you pull the tip off the alternator.

[Paykash]

Originally Posted by ScottSinger

next time it happens, have a long stem screwdriver with you and carefully place the metal flat tip on the alternator and bring your ear to the handle end and listen. if it is the alternator there should be no doubt as you pull the tip off the alternator.

ok so if it's the alternator, the sound should be louder when I put the screwdriver to it and listen?

[overcoil]

Originally Posted by Paykash

ok so if it's the alternator, the sound should be louder when I put the screwdriver to it and listen?

The screwdriver will transmit the noise directly and distinctively.
Like a stethoscope.

You need to be careful with a running engine, the screwdriver slipping, your face in harms way