Whistling sound from drivers window

[jxu]

Hey guys got this weird problem on my 335i. Basically when i have the drivers window down, and get to 80Km+ theres a loud whistling sound that comes in. Took it into the dealership and they said its the side mirror, he put his hand on top and waved it up and down showing me its teh wind on the mirror that caused it. He then showed me this same thing on another 335i, saying it happens to every single 3 series. Any one got any idea how to fix this or more info on this for me to go back at the dealer with, i dont know what can they do>.<

[Stephanie]

This is a very common problem from what I hear... I've seen this posted on a few of the rant threads on e90post...