How frequently does it thump? Every bump? More in cold weather?My 2016 200s has a thump noise coming out of rear passenger side when going over bumps. Has anyonr determined what typically causes this?
My thought was the same since the clunk goes away after it happens. I found my bump stop down once after I heard it. So I believe you’re dead on with your diagnosis.How frequently does it thump? Every bump? More in cold weather?My 2016 200s has a thump noise coming out of rear passenger side when going over bumps. Has anyonr determined what typically causes this?
In my case the dealer had to replace every component in each shock absorber assembly (shock, mount, splash shield/bumper) before the noise was cured for a couple years. Then last winter it came back intermittently, most frequently when carrying rear seat passengers and with colder temperatures. When I took it in to the dealer they could not duplicate the noise, which was extremely frustrating. I even went back in with my wife and rode with techs/advisors in the rear seat and it still wouldn't do it over bumps where I previously had the issue. A notable difference was that car had been kept in the warm shop overnight, and the weather was warmer than it had been on the day we attempted to diagnose it.
After wasting a whole lot of time with no result, and a lot of frustration, I resolved to let it go until it became a constant issue that they couldn't fail to recreate. Unfortunately, it still hasn't a year later, though the intermittent symptoms did recur again when it was colder, and most frequently with rear seat passengers.
My primary theory is that the splash shield and bumper, which ride on the shock shaft above the shock and below the shock mount, can get stuck on the shaft in a relatively low position due to inadequate lubrication particularly when combined with moisture in freezing conditions. This wouldn't cause any noise until the shock compresses more forcefully than usual, such as when dropping into a pothole and/or under heavier than normal load. In that situation, I suspect the bumper, instead of riding smoothly up the shock shaft as it's supposed to, sticks momentarily before releasing with extra force causing it to shoot up and collide with the shock mount making the thump. So, before next winter I plan to see if I can clean and lubricate the shaft and make sure that the bumper slides smoothly. FCA specifies that it should be lubricated with Mopar zipper lube, which I believe is a silicone based grease.
If that is not the cause, then all I can guess is that the valving inside the shock might stick occasionally, particularly when cold. But since the first time my dealer fixed the issue they replaced the shocks and did not eliminate the noise and it only went away after they replaced the dust shields/bumpers, and also because it occurs on both sides with my car, I like my first theory of inadequate lubrication of the bumpers better.
The particularly frustrating thing is that it's tough to get dealers to experiment and troubleshoot for you unless they first duplicate the issue. So I'd suggest if you take it in, you find a place nearby the dealer where you can consistently get the noise to occur and you are certain you can demonstrate the problem.