[TJZ67201]

Someone mentioned that the F22 2-Series also has a similar thump from the rear suspension. Stiffer springs supposedly stopped the noise. I wonder if that would also help reduce the G42’s noise.

[Fronzdan]

I’ve been “trying to ignore the thump” for about a month now. It’s just odd that no one can figure it out.
To me it seems like something is loose, like the slight bumps are more shaking things up and down causing whatever is loose to bounce and hit something else. I think we’ve ruled out an actual strut or mount problem because people have had these replaced. Plus it’s only on the left side.

So what might stiffer springs do? It might put things on that side under more tension. Or is it because the different springs raise the rear end slightly? I guess if it’s something in the suspension that’s loose or hitting something, it might prevent whatever it is from hitting something. Sitffening the dampers makes it worse though. Hmm..

I wish I could poke around while the car is on a lift. I just have a feeling it’s not anything in the actual suspension but something that’s shaking more/less based on the how firm the suspension is….something like the exhaust system.

The fact that’s it’s just one side is interesting. I can roll over the same bumps on the left side and no sound.

[TJZ67201]

Originally Posted by Fronzdan

I’ve been “trying to ignore the thump” for about a month now. It’s just odd that no one can figure it out.
To me it seems like something is loose, like the slight bumps are more shaking things up and down causing whatever is loose to bounce and hit something else. I think we’ve ruled out an actual strut or mount problem because people have had these replaced. Plus it’s only on the left side.

So what might stiffer springs do? It might put things on that side under more tension. Or is it because the different springs raise the rear end slightly? I guess if it’s something in the suspension that’s loose or hitting something, it might prevent whatever it is from hitting something. Sitffening the dampers makes it worse though. Hmm..

I wish I could poke around while the car is on a lift. I just have a feeling it’s not anything in the actual suspension but something that’s shaking more/less based on the how firm the suspension is….something like the exhaust system.

The fact that’s it’s just one side is interesting. I can roll over the same bumps on the left side and no sound.

I agree with what you’re saying. To me it sounds like I hear the noise when the springs are at full extension/rebound after a minor road imperfection. My thinking was that stiffening or lowering might change the rebound but another forum member just confirmed he still has the thump after lowering with Eibachs.

I had my car up on jacks in the garage and confirmed it is not the exhaust in my case. I was able to freely move the exhaust while under the vehicle and it made absolutely no contact with anything from the downpipe all the way to the tips. I also tried to play around with the fuel tank which is near where the sound originates. I could not recreate any thumping noise but I did not fully rule it out. Might be worth looking into further, I just don’t have time to get under the car to look just yet.

[Jabmwo]

I sold my M240 which had the problem. In one hand I couldn't stand the rattle and in the other the attitude of BMW NA was absolutely disappointing and felt cheated. After my local BMW dealer acknowledge the issue, had the car three times to "fix it", including changing the rear struts and mounts, removing the fuel tank and installing it back, etc (they had the car for one month at one time) without any luck, to the point BMW Corporate got involved.... They were very polite and helpful until I tried to have them buy back the car (Lemon Law). Then they started to argue "is it normal car noise". I even made a complain with the North Carolina AG office but they just contacted BMW NA, and asked their position, BMW replied "is normal" and the NC Attorney General Office did nothing.
I was so disappointed. I sold the car with 6,000 miles at a loss. Went back to a used manual F22 (230) and I'm having a lot of fun... without rattles!
I feel your pain guys. Hope BMW finds a fix.

[Fronzdan]

Originally Posted by TJZ67201

I agree with what you’re saying. To me it sounds like I hear the noise when the springs are at full extension/rebound after a minor road imperfection. My thinking was that stiffening or lowering might change the rebound but another forum member just confirmed he still has the thump after lowering with Eibachs.

I had my car up on jacks in the garage and confirmed it is not the exhaust in my case. I was able to freely move the exhaust while under the vehicle and it made absolutely no contact with anything from the downpipe all the way to the tips. I also tried to play around with the fuel tank which is near where the sound originates. I could not recreate any thumping noise but I did not fully rule it out. Might be worth looking into further, I just don’t have time to get under the car to look just yet.

What about the stock “exhaust tip” openings? I was washing it last week and noticed when cleaning around those ports they wiggled a little and clicked against the bumper slightly. Not the same sound by any means, but there was a sound. I was going to remove the right side and see if that changed anything. It’s a stretch because I doubt they would make that deep a klunk. I guess anyone who’s done the quad tip upgrade would know.

[TJZ67201]

Originally Posted by Fronzdan

What about the stock “exhaust tip” openings? I was washing it last week and noticed when cleaning around those ports they wiggled a little and clicked against the bumper slightly. Not the same sound by any means, but there was a sound. I was going to remove the right side and see if that changed anything. It’s a stretch because I doubt they would make that deep a klunk. I guess anyone who’s done the quad tip upgrade would know.

I should have specified lol - I removed the stock exhaust “rings” and I have the quad tips installed. Still same noise no change there

[Fronzdan]

Well check that off the list lol.
Hmm…continuing to grasp at straws…the gas fill is on that side…how about the pipe leading to the gas tank?

[TJZ67201]

Ok so I was bored after work and realized I still have my ramps in the garage so I got under the car. It’s not the gas tank or the filler neck. I did a lot of shaking and prodding and cannot recreate the noise. Plus I just realized the 230i and the M2 both use the same fuel tank part number and they don’t have the issue, at least from my research. Which makes me believe it would have to be related to the M Performance adaptive suspension…

The only next step I could foresee is to get a pair of chassis ears and to try to isolate the exact source of the noise. If that’s even possible… I don’t have any experience using that tool

[Madkows]

New guy here with same issue. Can’t recall where I read it, but I’ve seen where some suspected the issue could be with the valved exhaust baffle knocking around in different states (hence why the sound is more pronounced in sport mode/sport+ than comfort)…swapping out exhausts fixed the issue. TBH, the sound is there, but I’m able to live with it…not nearly as annoying as the rear deck rattle I had on my E46 M3.

[Pentland]

I’ve asked before and not seen a reply but can anyone record the noise please?

I certainly don’t seem to have this nuance so very interested. May be it’s a LHD thing?

[Fronzdan]

Originally Posted by Madkows

New guy here with same issue. Can’t recall where I read it, but I’ve seen where some suspected the issue could be with the valved exhaust baffle knocking around in different states (hence why the sound is more pronounced in sport mode/sport+ than comfort)…swapping out exhausts fixed the issue. TBH, the sound is there, but I’m able to live with it…not nearly as annoying as the rear deck rattle I had on my E46 M3.

Ok this is interesting. Is this the infamous exhaust valve that everyone wants to keep open? Or is there another valve in the muffler for example, which makes the exhaust louder depending on the driving mode? Like I’ve said, it has an exhaust kind of hollow thumping sound to it. And I’ve noticed that on some roads where you get a series of those little bumps…it kind of gets the whole car bouncing up and down sort of, and I can hear like a couple clunks. Closer to a rattle.
Of all the things tried that didn’t work, I don’t think anyone’s tried replacing the muffler/exhaust. I guess the question is, has anyone who has a different exhaust hear it??

[Madkows]

Post #149. Dude installed AC Schnitzer exhaust and the problem persisted. Scratch that supposed fix I guess.

[TJZ67201]

Originally Posted by Madkows

Post #149. Dude installed AC Schnitzer exhaust and the problem persisted. Scratch that supposed fix I guess.

Exactly. Plus I was able to get under my car and shake the exhaust pretty well, no rattle or thump sound at all. And my valves are usually forced open using SST flap controller module.

[Fronzdan]

You had me looking at new exhausts for a moment there.

[grooveK]

anyone else get the feeling that in ten years, people are going to be wanting rear suspension thump as a feature for their cars... like burbles and pops?

[Rdurty2]

I wonder if the car will let you drive if the EDC controller is disconnected. If it did it would be an interesting test.

[Madkows]

Thinking this issue is a feature not a bug.

[Antique-ace]

Build date is 08-05-2021.
I have a service appointment on 3/12/24 to diagnosis and fix the rear thump.

[TJZ67201]

Originally Posted by Antique-ace

Build date is 08-05-2021.
I have a service appointment on 3/12/24 to diagnosis and fix the rear thump.

Good luck, keep us up to date.

Here’s another data point. I bought a few cases of water last night and put them in my trunk. Seems like the extra wait over the rear axle significantly reduced the thumping sound. Maybe the EDC is not properly calibrated for the weight of the vehicle?

[Rdurty2]

I unplugged the EDC from the rear passenger strut and drove all the roads that really bring out the noise.

No difference, thumping is still there.

[Gravityct]

Could it be spring/spring perch shift or play?

[E23745iTurbo]

Anyone try removing the actual shock mount?