Location: Panel between the cup holders
Noise description: Noticeable, ticking/rattling on rough pavement.
Fix method: The panel between the cupholders, although constructed well, uses two aluminum guides that, naturally, rattle in their respective holders. I don't have a picture, but if you use a pry tool and pop the left and right side, you'll see what I mean. In the center, there are two silicone guides, the pins that slide into these guides rest on the panel itself, and they vibrate inside the panel, in the slots where they reside. What I did was use 40 year silicone clear caulk and sort of "glue" them in place. Since it's not permanent, the silicone acts as a resonating absorption mechanism. I used the same caulking for all the guides in the A and B pillars as well as felt the heck out of those metal areas.
Thread link? None
Location: A pillar
Noise description: Noticeable, rattle/echo on bumps, annoying, hard to trace.
Fix method: Remove SRS cover, use T-25 to remove screw, pull A pillar out and up. There is a shitty plastic clip that resides in a groove in the A pillar cover itself. Use 40 year soft silicone caulk to "set" this plastic clip in the groove, it will act as a damper for it's rattling. Cut 1"x1" thin felt strip and place over the hole where the clip will attach to the metal surface. Punch hole in the felt after applied. This is the cause of the echo, the plastic against the metal. Felt any areas you see where plastic may contact. Where the A pillar meets the dash, apply krytox sparingly as this area is known for a "squeak/creak". Re-attach in the reverse.
Thread link? None
Location: B pillar
Noise description: Noticeable, rattle/echo on bumps, annoying, easy to trace.
Fix method: This is sort of a pain in the ass, as yo have to remove the plastic door entry strip first (front) and just remove partially the passenger/rear entry strip. You can then pull the B pillar from the bottom outward and down. There are two shitty plastic clips that are similar to the A pillar, they need to be silicone caulked to lock them in place and cease their rattling. You need to felt EVERY piece of metal you see. Especially over the holes where these clips reside. Punch holes in the felt over the holes. On the underside of the B pillar cover, top, you'll see a plastic groove that meets the upper section. This rattles against this upper section. Apply felt to the upper section where this piece will meet. Re-attach in the reverse, BUT, apply krytox to the underside of the entry plastic strips as these tent to creak like a bitch.
Thread link? Many, with no real solution.
Hope these help some folks out. I am completely shocked that both the 335 and the M3 have so little insulation in the pillar areas. They are a major source of acoustics in the cabin and cheap to throw some on there during build time, and weigh NOTHING! Good luck. None of the felt applied here is visible, and the cabin is worlds quieter.
08 E90M3 6MT Alpinweiss/Carbon/BPMSport 91 octane tune/BPMSport Feature coding/BMW Pedals/Dinan Exhaust/Alcantara Wheel/Rear Fog Switch/Rattle fixes
Last edited by thekurgan; 02-12-2013 at 03:51 PM.