High pitch buzzing noise from engine

[Rausky]

Hello all,

I purchase my first M car a few weeks ago. 2008 E92 M3 with 95k on it. PPI was done and came back clean, I immediately did rod bearings just to be safe though. I noticed when I first bought the car that there was a high pitch buzzing noise coming from the engine whenever I would apply the throttle. It does it on cold start as well for about a minute then once the engine is warm it goes away, until you start driving and giving it some gas. I asked my tech about it when the rod bearings were being done and he says everything looked ok, so I'm not incredibly worried about it being something really bad but it's very annoying. Maybe a pump or throttle body actuators? I did a search around here but didn't find anything that sounds like this. Thanks!

[Redd]

Sounds like either heatshield vibration or pulley squeak to me.

[Rausky]

Originally Posted by Redd

Sounds like either heatshield vibration or pulley squeak to me.

I thought it sounded like the pulley too. Is there a way to diagnose it easily?

[Redd]

I've never tried to do it myself. You might need to take it to a mech.

[bmwm3s65]

I had a similar sound on my engine, I just noticed it recently after I've had the car for 2 years. Mine was coming from the oil filter housing.

[Rausky]

Originally Posted by bmwm3s65

I had a similar sound on my engine, I just noticed it recently after I've had the car for 2 years. Mine was coming from the oil filter housing.

Did you fix it or just leave it? Was it just vibrating against something?

[kyrix1st]

Likely alternator or pulley. I had this as well and my alternator failed on the highway. check voltage.

[bmwm3s65]

Originally Posted by Rausky

Did you fix it or just leave it? Was it just vibrating against something?

I just left it alone. It was not a vibration as far as I could tell. I chalked it up to normal operation of the car, that I had not noticed before.