Recently started to hear a faint metallic buzzing noise coming from the front passenger side. However, it doesn't seem to be linked to going over bumps or the famous vibration at idle.

Instead, it seems to be linked to speed. I only hear it around 120km/h (thats 75mph).

Any thoughts on what it could be?

I checked the front mudguards and it seems like the passenger side one is making a different (louder, and more metallic) noise than the driver side one, so despite the horribly unscientific hypothesis, this is my first guess.

My other guesses:
1. Dealer left something in the door panel when fixing the door rattle (related to speakers/bass, used TSB)
2. Its the screwdriver bit I stupidly lost in the dash/glovebox area 2 months ago. Could never find the darn thing, but it doesn't make itself obvious. Plus, if this were it, wouldn't it rattle like crazy going over bumps and not driving on smooth roads at 120?

 

i just started noticing the exact same noise. Its driving me nuts. I get it right above 100km/hr, i think it must be aero related. I tried driving with the mirror folded and it didnt help. Might be something loose under the car. Have you had any luck solving this? Thanks.

Thomas