I’ve had it with the rattles. I decided to find every single rattle and fix it. My father took the car for a ride on a pretty bad road and I was sitting in the back and front identifying rattles. This thread is about interior cabin rattles only. I’ve isolated a couple, feel free to add/comment.
Source #1: Rear left/right panels (High pitch rattle)
Cause: Broken push/lock pins
Solution: Remove panels, install new upgraded pins, add silicone sealant to the pins before pushing in place. Use dynamat to cover the back of the left/right panels. They are made from 3-4 parts and might rattle too.
Source #2: Rear deck (Low pitch rattle)
Cause: Upper wooden deck vibrates against the sheet metal beneath it.
Solution: Take 3 tennis balls, punch a hole on each and push them between sheet metal and upper deck through the trunk holes.
Source #3: Seat belt tensioner (High pitch, similar to source #1)
Cause: Something loose within the belt retracting mechanism
Solution: Replace the mechanism ($$$) or use dynamat around the belt mechanism. This will make the rattling inaudible within the cabin
Source #4: Cracking noise (like knocking sound plastic on plastic)
Cause: Seat belt lock hitting on the center console (when not engaged)
Solution: Push the seat belt lock away from center console (Simple eh?)
Source #5: Cracking noise (plastic on plastic) near passenger seat
Cause: First aid box front lid loose
Solution: New first aid box, remove it completely or use rubber around lid
Source #6: Rattiling noise (plastic on metal) near passenger (or driver’s) door
Cause: Speaker mounts are loose or broken
Solution: Aftermarket speakers (stock suck anyway)
Cause: Push/lock pins on door card broken
Solution: Remove door card, install new upgraded (with rubber washer) push/lock pins & apply silicone on them before pushing in place. Silicone does not bond, just provides a medium for sound dampening.
Cause: Door card against butyl sealant.
Solution: Apply dynamat on the lower section of butyl sealant or any other butyl based tape.
Cause: Metal clip holding upper window regulator steel cable
Solution: You need to find the rattling clip by feel since it’s burried in the upper section of the inner door. Follow the steel wire coming out from the window motor until you spot the guilty metal clip. Apply silicone around the metal clip to secure it in place. Nobody will ever look in there so put a lot!!
Cause: Window glass guides worn and playing around the rail
Solution: New window regulator mechanism unfortunately
Cause: Window regulator nuts not properly tight
Cause: Speaker grill rattling. It’s glued in place and sometimes gets loose from the rest of the speaker assembly
Solution: Glue it back in place. Black silicone works great!
Cause: The door card’s perimeter vibrates against the metal part of the door. This is because of too much bass and the inability of the push/lock pins to fully secure the door card in place. The “rattling” that is heard, is not a rattle but it’s the sound of the door card’s leather which has a very mild sticky surface which sticks and un-sticks on the metal part. I was surprised that after dynamating the door, new clips glued etc, I still had the rattles.
Solution: I took 4 pieces of thin rubber (20mm x 10mm x 1mm) and squeezed them between door card and metal (bottom,left,right sides). Voila. No More Freakin Rattles
Source #7: Squeeking sound when slowly going bumply roads, uneven surfaces (chassis flex)
Cause: Rubber window seals dry and squeeking against the glass.
Solution: Apply silicone grease on all rubber seals, leave it for a couple of days and wipe excess with a clean cloth. Paper towels not recommended.
Source #8: Knocking sound (plastic – plastic) around dash area
Cause: Loose dash trim, specially at the right side area of the headunit, where the HU trim is connecting with the passenger side trim. They are both held in place with a single pin which tends to get loose after time.
Solution: Remove trim, remove female plastic pin holders (in dash) and replace with new ones.
Source #9: Knocking sound (plastic to softer plastic) around passenger side
Cause: That thing on the roof of the car that you hang your hand from it(sorry don’t know how it’s called) tends to get loose and vibrates against its metal guides.
Solution: Remove 2 covers, remove 2 screws, bend the metal guides so that they push the handle tight.
Source #10: Knocking sound (plastic to plastic) inside dash
Cause: Aftermarket wirings behind headunit, such as wire taps are vibrating against the plastic A/C box.
Solution: OEM Cloth tape. Wrap everything behind HU and they will never rattle again.
Source #11: Knocking sound (plastic to metal) around passenger/driver seat
Cause: Plastic covers around seat vibrating
Solution: Tape the covers from the inside or apply dynamat from inside
Cause: Coins dropped in the seat rails
Solution: Clean the car
Source #12: Squeeking sound (plastic to plastic) around center console
Cause: Armrest mounts rubbing around console and on mounting bolts
Solution: Spray silicone grease on the armrest mounts and on mounting bolts.
Source: #13: Whistling sound (around HVAC)
Cause: fan inside of HVAC full of dust and bearings are wearing down
Solution: Cheap replacement control unit from ebay
Solution: Blow compressed air through the small finned hole in the front of the unit. Computer hardware cleaning compressed air (can) will work fine
Source 14: Another knocking style noise from glovebox area
Cause: This took me a while… The glovebox hangs by 1 strap on the left and one damper (Glovebox damper on realoem) on the right with 2 pins. It seems that there is excessive play between the damper and the glovebox especially once closed. The damper can move a few mm up/down because the hole in the glovebox is too big for the pin.
Solution: I took the glovebox off, closed the hole that the pin inserts with high strength epoxy glue, let it dry, and re-drilled it but with smaller diameter hole this time. The lock pin now inserts in place but does not allow movement at all.
Source #15: Another rattling from the rear deck area; Antenna amplifier & wirings behind pillar
Cause #1: The antenna amplifier is not tight and shakes a bit against the metal.
Cause #2: Wirings and plastic connectors shaking agains the rear window glass & metal
Solution #1: Remove antenna amp, lay a piece of rubber between the amp and the metal, re-tight the 2 T20 screws that hold it in place
Solution #2: Wrap all the wirings with cloth tape and using a wider tape, stick them on the metal so that they don’t move around.
Soucre #16: Speaker grills
Cause: Held by 6 plastic tabs at the perimeter of the grill, sometimes they get loose/break, and the speaker grill rattles agains the rear deck.
Solution: Remove speaker grills and either replace with new ones or apply a layer of black double face tape at the perimeter of the grill. It should stick it in place and prevent rattling.
Source #17: Rear headrests
Cause: The 2 shafts that hold each headrest have some gap between the headrest. It’s not entirely foam within the headrests, there are 2 plastic guides which the 2 shafts slide in place and cause a knocking sound.
Solution: Remove both headrests, remove both shafts from each headrest, wrap a very thin layer of cloth tape on each shaft (just one round) and insert back in place.
Full link: http://forum.e46fanatics.com/showthread.php?t=605933&highlight=guide+rattling+coupe&page=1