[TJZ67201]

Originally Posted by J-RO

Does the G87 have the same problem?

To my understanding no. You cannot option the same adaptive suspension on the M2, its more stiff and track focused

At this point I am 95% sure the noise has the be coming from the adaptive dampers. I’ve done a lot of other troubleshooting and everything else seems solid

Edit:
Check user BoilerM posts, he seems to have the solution! Expensive, but maybe worth it IMO

[BMWM.D.]

Bringing this one back. I started the original “suspension thump” thread, and am a BMW tech as some of you know. I replaced both of my rear shocks and mounts, and the thump is still there. No service bulletins or Advanced Information on this that I’ve seen. I believe they all do it, and it’s more or less normal.

That said, I’m going to have to tear my rear shelf out to resolve what is likely the plastic vent vibrating against something. I’ve also had torsional creak noises from the shelf (like when going up a driveway sideways) for a while. Since I do this stuff for a living, my motivation level has been a little low as far as going after this. Think it’s finally time to dig into it.

[Littlecoupe]

Originally Posted by BMWM.D.

Bringing this one back. I started the original “suspension thump” thread, and am a BMW tech as some of you know. I replaced both of my rear shocks and mounts, and the thump is still there. No service bulletins or Advanced Information on this that I’ve seen. I believe they all do it, and it’s more or less normal.

That said, I’m going to have to tear my rear shelf out to resolve what is likely the plastic vent vibrating against something. I’ve also had torsional creak noises from the shelf (like when going up a driveway sideways) for a while. Since I do this stuff for a living, my motivation level has been a little low as far as going after this. Think it’s finally time to dig into it.

We appreciate your feedback on the project. I've personally had a lot of cold-weather expansion/contraction crackling going on from the rear of the car, to the point I think I may need to remove some things and add padding. It's getting a bit ridiculous as this point.

If you do remove the parcel shelf, I'm curious if you as a professional can confirm if there is no way to remove the shelf without removing at least the C pillars. Or, can you remove the left and right side leather pieces (on each side of the rear seats) to access the bolts holding the lower part of the C pillars, and then remove the C pillars without removing the rear window plastic side trim (big panels) to get at the rear parcel shelf?

I'd prefer to remove as little as possible if I can help it, but I do think I should pull out the parcel shelf and add some insulating material to the plastic vent on it.

[IanH]

Have we ruled out the floor of the trunk causing the thump? it happens when you go over bumps?

I've never heard it but I did notice when detaching my battery that it is basically not connected to the car in any way. I keep a loaded crate of detailing stuff in my trunk so that would probably stop it from moving.

[TJZ67201]

Originally Posted by IanH

Have we ruled out the floor of the trunk causing the thump? it happens when you go over bumps?

I've never heard it but I did notice when detaching my battery that it is basically not connected to the car in any way. I keep a loaded crate of detailing stuff in my trunk so that would probably stop it from moving.

Yes. Trust me I tried everything. Fully disassembled the trunk. And the undercarriage panels. Even thought it might be fuel filler neck or the gas tank. None of which were the culprit. I also created a whole tread about removing and sound deadening the rear parcel shelf. Also fully removed the rear seats.

My thump is now completely gone only after replacing the suspension.

EDIT: thought this was in the thump thread 😂 Either way, the thump is its own beast. I WILL ADD: the rear parcel shelf vent does cause some noise and creaking. After sound deadening, that was eliminated.

Edit 2: to add, to my knowledge you absolutely have to remove the lower door trim and back seat trim (as mentioned in my OP) as well as the C pillar. Those parts are all interconnected and I saw no way to work around that when I had my whole back seat torn apart.

[Littlecoupe]

Originally Posted by TJZ67201

EDIT: thought this was in the thump thread 😂 Either way, the thump is its own beast. I WILL ADD: the rear parcel shelf vent does cause some noise and creaking. After sound deadening, that was eliminated.

Edit 2: to add, to my knowledge you absolutely have to remove the lower door trim and back seat trim (as mentioned in my OP) as well as the C pillar. Those parts are all interconnected and I saw no way to work around that when I had my whole back seat torn apart.

Thanks for this. For the trim, I did see you mentioned you thought you need to remove everything to get to the parcel shelf. I was hoping there was some kind of trick...

That said, it would probably be better for me to take everything apart and add tape/padding to all plastic on plastic surfaces. It seems like every panel suffers from expansion and contraction noises especially in huge temperature fluctuations.

As for the parcel shelf itself, did you add any material between the vent and the shelf? When you said you added sound deadening, I don't recall if that was just the areas I saw in your pictures, or if that was also on the parcel shelf vent since that looks to be plastic on plastic as well. Mine definitely creaks if when you put pressure on it, but more annoying is the plastic-fork-cracking noises that are most prevalent when the car is left in the cold and then warms up. It lasts for about 30 minutes and then settles down, which is ironically the length of my whole commute...FFS.

[TJZ67201]

Originally Posted by Littlecoupe

As for the parcel shelf itself, did you add any material between the vent and the shelf? When you said you added sound deadening, I don't recall if that was just the areas I saw in your pictures, or if that was also on the parcel shelf vent since that looks to be plastic on plastic as well. Mine definitely creaks if when you put pressure on it, but more annoying is the plastic-fork-cracking noises that are most prevalent when the car is left in the cold and then warms up. It lasts for about 30 minutes and then settles down, which is ironically the length of my whole commute...FFS.

Yes, I used 2 different products for sound deadening. Kilmat metal stuff and some brand off Amazon foam sound deadener, I’ll paste the link below.

For the rear parcel shelf, I would recommend using only the foam. That is plenty to isolate and provide a barrier to prevent the plastic creaking against the metal. Just cover all the metal that you see once you have the shelf removed. Get as close to the rear window as you can.

https://a.co/d/3ZH3pot

This is not my original photo. But this is the area you wanna target, circled in red.

[Littlecoupe]

The noises from the rear drove me crazy enough to finally tear everything apart and do some noise reduction. I removed the lower seat bench, rear seat bolsters, door sills, lower interior quarter panels, seatbelt holder trim, c pillar covers, rear parcel shelf and vent.

Noises I found, and I think I fixed:
- Creaks, squeaks and crackles from the vent on the parcel shelf. Fixed by adding “AggSound 157 mil” sound deadening foam from Amazon.
- I had an annoying “plap” coming from the rear over harsher bumps. I think I fixed it by adding some of the above foam inside the headliner near the C pillar. Will show in the pictures later the problem (was the bracket/air bag pressing against the headliner).
- Basically any wire or thing that I could touch and it would make noise, I put foam or felt tape behind it. Very methodical and OCD, lol.

As has been noted, it’s not really possible to get to the rear parcel shelf without massive disassembly. The bolt for the c-pillar cover is hidden by the lower quarter panel. It *might* be possible just release some of the rear retainers from the quarter trim after removing the seat bottom and bolster, get to that bolt, then remove the seatbelt holders, c pillars, then the parcel shelf, but you’d need to pull the quarter panel away and that could be problematic. If you’re going that far in, may as well just remove the whole quarter panel and door sills.

I will add some pictures and details here to add to the conversation in a subsequent post. Some things I learned:
- Remove the door sills from the front (engine side) to the back. I did the first one from the back to front and broke the tabs holding the back in place. I have JB welded the plastic and it feels solid, but be forewarned.
- Keep the speaker wires in mind. I was so engrossed in removing the airbag cable from the bottom of the lower quarter panel that I forget the speaker wire and destroyed the connector. I ordered a replacement one from Ali and spliced into the factory wiring.
- When putting panels back in, make sure the pins align before you start hammering away on them. In fact, try pushing the retainer in before you give it slam with your fist. I broke 1 retainer this way.

Replacement items:
White retainers for side sills (x7 per side): Part number 51-47-7-447-096
Blue retainers for lower quarter trim (x4 per side): Part number 07-14-9-136-882
Green retainers for lower quarter trim (x2 per side): Part number 07-14-7-129-310
Expanding rivets for seatbelt holders/parcel shelf (x8 total): Part number 51-11-1-908-077
White retainers for C pillar (x2 per side) (this might be wrong, you can use the blue one above, I did): Part number 51-43-7-001-491 – assuming they are the same as the G20 A-pillar retainers
Speaker connector: BMW part number 6925630-01, cannot buy from the dealer. Can also use PN (Tyco) 3-1452577-1

Disassembly:
Remove lower seat bench, clipped in 3 places at the front bottom of the cushion. Just pull up: Easy.

Remove seat side bolsters. 2x (T25 Torx…maybe), top and bottom. Pull out to remove. Note the big rectangle holder. Mine pulled out with some force. May be better to tilt the bottom of the bolster up when pulling out. Explained later for installation.

Remove 2x expanding rivets per seatbelt holder. Pull the center pin out with a trim removal tool or flat-head screwdriver, then pull out the plug. Pull the seatbelt holder out (held by tabs, comes off easy).

Remove door side sill trim. Start from the engine side and work toward the back. When removing, tilt the engine side up and pull out, there are two tabs on the rear side that you need to clear the lower quarter trim.

Remove lower quarter trim. Pin locations shown there. 6 lower pins are the round type. The 5 under the window are v-style metal clips. Remove the blue speaker connector (wiggle and pull up, it is tight), and remove the airbag connector from the body of the car to the panel (tab is on the back of the connector) if you’re removing that piece from the car. NOTE: if you drive the car with this removed, it will trigger a check control message. I needed to clear that message over the OBD, it didn’t go away after re-installing.

Remove C pillar trim by removing the lower bolt and the upper bolt hidden by the airbag plastic piece. Remove the airbag piece with a thin tool (like a jeweler’s screwdriver). Safer if you wrap the tool in electrical tape to avoid marring. After the 2 bolts (T20, I think) are removed, pull the panel out to release the pins, then maneuver by tilting the front up and pulling out. There is a tab that slots into the parcel shelf.

Remove the remaining 4 expanding rivets from the parcel shelf. Pull up and remove the colored wire speaker connectors from the speakers. Leave the black wrapped cables, those can stay connected. Pull the parcel shelf towards the front of the car and you will hear a sound, that is releasing from the vent which is bolted to the car body.

Remove the (4) 8mm bolts from the vent and pull it away from the body.

Sound deadening:
I added the foam to the area shown, basically anywhere that the plastic vent will touch metal.

For the other noise I had, see the piece marked with a green line. When I pressed on that, I would hear a noise in the headliner. I don’t know if it was the bracket, the airbag, or both. I pulled the headliner away from the roof a little, then slid some of the same foam into the headliner, it is affixed to the headliner side. Should not affect airbag operation, and the noise seems to be gone.

Reassembly is the reverse of disassembly, but I’ll leave some comments:
*Rear deck vent – Straightforward, put in place and install bolts.
*Parcel shelf – connect speakers, press into the vent (sides will feel loose compared to the center), then install the expanding rivets.
*C pillars – Line it up, look between the cover and mounting points to align the pins before pressing into place. One was not aligned for me and I broke the retainer. I used an extra blue one I bought and it worked fine.
*Lower quarter panel – Install speaker connection – works in either port. Install airbag connector if you disconnected. Line up the panel to the top metal clips, then look/feel that the pins are lining up to the mounting holes. These clips can be pressed in, don’t need to slam them with your fist. You do need to slam in some of the metal clips though.
*Seatbelt holder – align it, press into place, then put in the 2 expanding rivets per side.
*Seat side bolsters – I had trouble engaging the black connector with the white body-side connector. I removed the white connector from the body by tilting up and removing it. I clipped the white connector to the bolster, then re-attached to the body by tilting the bottom of the bolster up slightly then pressing it into place.
*Seat Bottom – Move the seatbelt receptacles so they align with the seat, press down and engage the front 3 clips.
*Side sills – start from the back by sliding the tabs into the lower quarter trim, then line up the retainers and engage.

[Littlecoupe]

Picture order:
Seat Bolsters top and bottom bolts + plastic rectangle retainer
Seat belt holder removal (expanding rivets)
Removed door side sills
Quarter panel retainer locations
Quarter panel removed
Speaker wires behind quarter panel
C pillar mounting
Speaker wires under parcel shelf
Rear vent
Rear vent removed
All parts removed (loose)
Sound deadening added to vent area
Problem area from other noise (added foam to the headliner)

[IanH]

Thanks for the great writeup and instructions!

[Littlecoupe]

Originally Posted by IanH

Thanks for the great writeup and instructions!

Most welcome! I always appreciate when other members offer this type of information, so I reciprocate where I can.

Although this process was a little stressful, I feel it was worth it for me. The rear of the car is basically silent now. I was less than 50% satisfied with the quietness of the car before, now it is probably 85%. The rest of the noise are little sounds from the front, but I'm not sure I can do much about them. Seriously, the rear quietness is night and day. Most of it was that stupid vent. The fact that (I hope) I was able to fix that plap sound too is a huge bonus.

If anyone else takes this on, just take your time. I only ran into problems when I got impatient. Don't get rammy.

[AdonisP91]

Originally Posted by BMWM.D.

Bringing this one back. I started the original “suspension thump” thread, and am a BMW tech as some of you know. I replaced both of my rear shocks and mounts, and the thump is still there. No service bulletins or Advanced Information on this that I’ve seen. I believe they all do it, and it’s more or less normal.

That said, I’m going to have to tear my rear shelf out to resolve what is likely the plastic vent vibrating against something. I’ve also had torsional creak noises from the shelf (like when going up a driveway sideways) for a while. Since I do this stuff for a living, my motivation level has been a little low as far as going after this. Think it’s finally time to dig into it.

What about the reported R_NE SEL-SEL-P-33-20000994548681-02 - 2024-10-16 ? Have you been able to confirm or read that TSB?