Leaderboard

Now you know why they give you a first aid kit under the passenger seat !!

I had a "chirp" sound on my 330Ci a while back which turned out to be the alternator. New brushes fixed it & bearing...yes im tight!!!!!

The air con pulley has a kind of slip bearing on it which would make this noise if the air con is off. Turn the air con on and see if the noise stops when the clutch on the pump engages. it definitely sounds like something attached to the belts rather than the engine itself. I had an old e36 4pot which had the pulley with the knock sensor on it. That bearing failed and allowed the pulley to move forward and back. Try pulling each pulley away from the engine and if one moves, it is a good place to start

The Belt Tensioners are another possible cause Dave

That’s A metallic sound. Does it change on revs? firstly check oil levels on the engine. I would think the noise is a bearing from a pulley. Most likely the alternator or air con pump.