LongS211

Hello W211-owners,

I bought an S211 E500 4MATIC and the Mercedes dealership replaced front and rear struts with Arnott parts before delivering the car to me. On normal drives, everything is functioning normally, but when taking the car on a 3-hour trip to the mountains, it starts excessive, pedestrian-head-turn-inducing clunking in the front. The slightest unevenness in the road makes it sound like the front suspension parts are hardly attached anymore. Neither raising the car's air suspension nor turning it off and on again changes this issue. However, when I drive back home, the issue gradually subsides and after a day or so returns back to normal.

As a result, neither Mercedes-Benz nor a highly rated independent shop were able to reproduce the issue and both checked the suspension (Mercedes even went through the related attachment points and made sure they torqued it all correctly) and found no visible play or wear. Given this issue is intermittent and severe, I imagine it can only have to do with the air struts. Has anyone experienced such an issue and would know where my mechanic should get started? The Mercedes dealership is a little far from me and they have had the car for two extensive periods of time with plenty of miles on their test drives without being able to reproduce it, so I'd much rather have the indy tackle this job with me, but of course don't want to pay for another sets of Arnotts either.

Looking forward to solving this riddle, thanks in advance for any help.

amosfella

Well, what's the elevation change on the drive approximately?? On another 3 hour drive not to the mountains does it do the same thing?

LongS211

I was thinking in the same direction, Arnott said they never heard about elevation-related issues, though. I live at around sea-level and the drive takes me to 7800 feet or 2377 meters. Outside of these mountain trips, I have yet to drive for 3 hours on end.

LongS211

Update: This continues to happen on extended trips of any kind and after more strenuous passages over rougher terrain (rough being less than stellar roads). I will continue chasing this issue and hopefully update this thread with a solution, but so far it looks like my struts are having an issue, but Arnott won't help me if I don't go through Mercedes Benz of Walnut Creek, who don't want to help me because they claim they don't hear the noise.

tjts1

Typical Arnott build quality. You're not the first to complain about this

Overheated

I'm chasing a similar noise that seems to emanate from the top of the LT front strut. I've read that the mount at the top of the strut becomes compromised and will make such a noise. Arnott has no qualmes about replacing it.

LongS211

First time I am hearing that I am not the only one struggling with this, normally I hear nothing but praise for these alleged improvements over OEM. I am almost inclined to build them all back to OEM now. If the rears are working fine, is it possible to only change the fronts back to new OEM units? Will that give me Sport and Comfort mode back or do I have to do all four corners OEM for that?

Bounder

Really? If Arnott isn't OE for MB, who is? Maybe it's MB build quality.

F1Fan

Most likely it is the Arnott air spring. They do have a lifetime warranty however. I've replaced the front left more than once. Getting a replacement from Arnott was easy. Any decent mechanic can probably swap it out under 2 hours.

Bounder

Thanks. Could you provide a link or snip showing there's a lifetime warranty honored by ARNOTT? Best I can find is a 2-year limited warranty on Arnott's website; otherwise additional warranty may be coming from shop you purchased from.

F1Fan

I must have been mistaken. Sorry about the mixup.

F1Fan

Just fyi, Bilstein is the OE maker for the air spring.

Arnott started supplying remanufactured air springs, then later started making their own.

rodneypierce

Arnott air struts are junk. I've now replaced two sets, and my third set is in need of replacement. They clunk and bang because the damping in the strut is gone, hence the issues on bumpier roads.