Originally Posted by higher' post='1001627' date='Sep 8 2009, 03:14 PM

This is a common problem with BMW. I had this on my drivers door for years and it drove me nuts. BMW service know about this and can help. This is what I found out / researched.
It is the rubber seals around the door / tailate, usually the exterior facing one's. You might notice they are worse after rain, or sun. Mine are worse after rain and then squeek and rattle like mad (for first year I though it was something loose in the car). After a quick wipe of hte seal with my hand or cloth (wiping of water or dust) they are perfect.
BMW will sell you something called Gummi Fledge (name might not be correct but phonetic spelling is) you just spray it onto the seals and it solved the problem it costs $10 per can. BMW technicians say they use it by the bucket load to solve this problem. Mostly they'll put it on as a mater of course during service.
Don't whatever you do be tempted to lubricate the seal with silicon grease, or vaseline, this will solve it for a couple of days but it will return, sometimes worse I did the same first-off. Remove the grease and clean seals with vinegar (yes vinegar) then use the Gummi Fledge, or just wipe clean when the noise starts. Hope this helps.

Originally Posted by narvselius' post='1002522' date='Sep 9 2009, 11:08 AM

Gummi Fledge = Gummipflege =>Rubber conditioner

I use it regular on all rubber sealings. Works great. Recommendable!