mb3ps

I've got a suspension issue (I think) that is most pronounced over a large speed bump, as demonstrated in the video below:


On washboard surfaces, or really bad roads, I get the same hollow, clunking sounds, instead of a nice firm thump, which is what I would expect from a car of this size (and from a MB). The sound and looseness happens on both front and rear axles, with the Airmatic suspension at normal height and raised, and in sport mode and non-sport mode.

There was an "inverse speedbump" (a large depression across the road) near my house, and the symptoms were also severe when riding over that. (The road hazard has since been fixed.) I would guess the symptoms are most pronounced when the strut is at its full or near full extension, and/or during the rebound phase, and when the suspension movement is rapid. If I crawl over bad surfaces, the symptoms do not exhibit.

I've only had the car six months, and at first attributed it to the large wheels and low-profile tires (nothing crazy though: factory AMGs with 245/40R18) and the sport package on this E. But, now that I'm more in tune with it, I really feel like something is not right.

I have brought it into the dealer once already, and of course, they couldn't find anything wrong with it, even though I demonstrated it to the shop foreman. The tech who then took it out "could not reproduce" the issue.

I've had cars before with bad struts, bad strut mounts, loose swaybar links...and it could be any of these things, or something else.

A friend with a similar car, a CLS550 also with Airmatic, says "something is definitely not right."

Any thoughts from the collective out there? Anyone with a similar issue that got resolved, and hopefully I can definitively point the dealer to during my next visit? (It's CPO, so I say "dealer," but I'll go to an independent if the supposed factory experts can't find out what's wrong.)

Much appreciated in advance.

konigstiger

Reference attached bulletin. Since they claim no physical problem provides reason to check control unit.

mb3ps

konigstiger, thank you, that sounds just about right!

However, I noticed the date on that bulletin was June of 2011. If my build date is June of 2014, shouldn't that fix already be in the Airmatic control module?

(Still going in for a second check, with some other cold-weather issues that popped up this week.)

konigstiger

Yes I know but since they're adamant that nothing is wrong justifies you're requesting to revisit.

thefisch

OP, I get a similar sound from the front (not the rear as I recall) on my 2011 E550 with airmatic when going over rough roads, not as much with speed bumps anymore. I said anymore because I noticed that sound during an initial test drive over speed bumps and the selling dealer had the flash repair noted above done. After that, it hasn't been as prevalent on speed bumps but I do still notice the sound on rough roads. Like you, I have been told the airmatic system is working fine.

Thanks for taking video and sharing this - hope it leads to a resolution.

Oda112

Mine does the same thing, it's worse when it's cold outside. Called MB, they said I need to pay 175$ for 1 H of labor. Still haven't done it but I'm thinking it needs addressing at some point. It is definitely a rebound issue, I can hear it and sometimes feel it, especially over higher speed bumps or drainage holes when getting out of steep driveways.

300SE1993

I had a similar sound on my S430. Never found anything wrong and just ended up living with it for the 40K miles or so I put on the car. If that's any indication, then Mercedes has been having this issue for a long time across multiple models with air suspension. Hopefully you have better luck in tracing down the problem.

2014CL600

My CLS550 was making the same noises. I decided after 2 months I had had enough. I replaced both front struts and now the car is like a new again. The dampeners go out because the gas struts lose their charge. It was like every little rut, bump and road imperfection would sound like HELL, it was just HORRIFIC. It got worse in cold weather, that's when I decided to change them. I got mine for 930 each and 180 installed. Put in the Mercedes OEM ones. Didn't last but 40K miles. Hope I don't have to do it in another 40. Had the same issue with my Jaguar XJR.

ahmadk

I have the same issue with my 2011 E550 and it gets a bit louder in cold weather.
I've been meaning to raise the car to check out for worn components but not having a garage and not wanting to lay on my back to check for stuff is keeping me from doing so.

I'm kinda relieved that I'm not the only one experiencing this

2014CL600

My noise had been driving me crazy until I finally got my warranty company to pay for the RH side but they declined to fix the LH side. I'm suing them for breach of contract because their 5th adjuster told them they were both bad but decided to replace on first then the other if it didn't resolve the issue. After half the noise was going they said, "we don't fix noises only defective parts". Ill fix them good. When I decided to fix it my self the strut had leaked oil all on top of the unit. What happens is the seals go and the gas escapes and the strut is only working off of the bag. Once the bag blows, your done for. Replace which ever side is bad. If its coming from both side replaced both. I've tried Arnott but they are HORRIBLE. My Jaguar had 4 replacements and the noise didn't go away, so I traded it for this car and had the same issue!!! URGH! Well, since I was able to get an extended warranty they paid for the RH side. They will pay for the LH side, trust me. I would only go with the originals instead of the Arnott or the ones of Ebay. The problem is the remand ones on Ebay are just exchange only with only the replacement of the bags, not the internals. Arnott is the same way. You get what you pay for. If I had sent mine in for a rebuild I would have gotten the exact same issue back. They don't do anything but replace the bags on the rebuilt units. I am hoping that these last longer than 40K mile. I will say, it's like riding on a cloud again without any noise. Best of luck.

MercFiveHundred

I have the same issues 2014 E550, but unbelievably, when dealer test drives it disappears. There should be a damper pressure test for all 4 dampers in STAR. When I get the chance I’d have the dealer do a diagnostic to maybe prove they are defective. If not, I assume it’s something electronic causing the dampers not to function correctly.

Side note: car isn’t driving so great in corners and over bumps. Same was happening in my 2003 E500 and after getting the “right” alignment, car drove like new again. “Right” alignment is setting ride height with STAR and a romness tool then performing the actual alignment. Most dealerships will charge more for this at around $300+.

Would be great if techs on the forum could opine...

2014CL600

If all of your suspension has been tested to be good, it is the internals of the strut. Once the gas bleeds out you, no matter how many tests they do, you will never be able to find the problem. Replace the struts and the noise and handling will be just like it was when new.

TeeEl

I'm actually experiencing this as well. I wonder if mine is also exacerbated by the cold because I'm just noticing it whereas I wasn't a couple of months ago just after I bought the car. A couple things I've noticed: when the car is on "comfort" suspension the noise decreases, and when I "raise" the ride level via the button it all but goes away. It sounds like I'm going to be on the hook for new front suspension which irks me because when I had a pre-purchase check done on the car they didn't mention it at all.

MercFiveHundred

2014CL600

NizaamK

So I have a 2010 model E350 with airmatic suspension and I have this irritating rattle on the right front. It sounds as if it's a shock mount. My car has over 300,000kms or 180,000 miles and still goes well and have had no other issues besides a sagging rear which was sorted after I replaced the airbags. I've replaced lower control arms, replaced the front stabilizer links, replaced the upper control arms and now I'm dreading front shocks. If my car goes up on a 2 poster lift, for the first few kms the noise goes away completely. Then it comes back. The longer I drive, the worse it gets. In sport or comfort mode its the same. I really enjoy the car and it's served me well. Any source for affordable OEM front shocks? Thanks I have been a member for a while under username Turbo6 but I seem to have lost the credentials

Arrie

It probably is the front air struts. I just changed mine in my 2010 E550.

2014CL600

The bag may be good but the seal on the top has failed and allows the gas to depressurize. My CLS was so noisy that once I changed them, you could see the oil that was on top of each strut. Now, it’s so quite, just like new again. If your mechanically inclined, it’s actually very simple to replace it yourself.

bmwpowere36m3

I have a similar knock that occurs when going over speed bumps... not on the compression, but rebound stroke. The only bushing/balljoint on the '11 E550 that "may" be due for replacement is the thrust arm bushing (some cracking around inner sleeve and overall soft) after throughly checking the front-end.

I still need to check the software version of the Airmatic per the TSB, but I noticed play in the strut mounts when doing some work on the car. Usually OE strut mounts are some form of a bearing which is rubber encapsulation and isolated from the mounting feature itself. I can understand some movement or give due to the rubber. This feels and sounds like straight up play/wear in the bearing.

Doesn't help the mount isn't serviceable on the Airmatic struts..

The video shows both sides, the "shake" is the car itself moving on the lift. However one can see the inner part of the mount/strut/airline fitting moving in relation to the outer portion. The passenger side has more movement, but both are equally noisy. I was manipulating, pushing back/forth, inside the wheel well the metal "dome" of the strut above the bellow