I recently bought a 997 C4S and i noticed that a speeds over 200km/h there is a whisle noice which is very annoying. I have tried tightening my mirrors but the problem is still there.

Does anybody have a clue what is the reason for this whisle?

 

I wish we could have that problem in the USA.....

Yves

 

Is it coming from one side more then the other ?

 

Likely the horizontal seam on the mirror. Mine does that on the passenger side.

 

I believe is from the left hand side of the windshield. Maybe there is something wrong with the rubber seal?

 

Years ago I had the same issue with my ex BMW M Coupe, except it happened only above 220 km/h. Only one mechanic dared to ride with me to find out the problem and as soon as he pushed out on the top right part of the windshield, the sound was gone.

Air pressure at that speed tends to slightly push the windshield "inwards" and sometimes there is a gap in the seal that causes the whistling sound. In my case, they had to re install the windshield and put a new outer rubber seal. Problem solved.

 

Hey it sounds like same problem I had. It came from passenger side mirror.
I couldn’t narrow it down until I brought it to the body shop.
About hour later he said the car is ready.
He told me that there is a gap between back side of the mirror and he put some kind of liquid sealer around the gap.
I borrowed someone’s side mirror pic to show you where the gap is. check my pic, see the yellow line that I drew. That’s the gap that it was making high pitch sound when I go over 50 mph.
Good Luck!

 

Likely the horizontal seam on the mirror.

 

Thanks for your advices. I think i will try using masking tape on various suspicious areas and try the car out until I hit the spot. As soon as i am 100% sure of what is causing the whisle i will visit the body shop to fix it.