jb1894

Long time lurker and 1st time poster. I recently bought a 2017 W205 C300 Sport (VIN# 55SWF4KB0HU203867) not from Mercedes directly; however, I am still covered under the MB new vehicle warranty). I got new OEM brakes struts, and control arms replaced by the dealership that sold me the car (at no cost to me). Admittedly the current tires on the car are crap, and I am in desperate need for an alignment. I am scheduled to install new set of the OEM run-flats next week - I have scanned over the countless threads about run-flats vs non-run-flats and chose to keep the run-flats since I live in NYC.

Apart from the tires and alignment, I now have a constant creaking sound that seems to come from behind the dashboard as I am driving. I suspect that it is coming from behind the center console. I have attached a video of me driving the car today wherein you can clearly hear the sound. After much investigating with the service department at the dealership that sold me the car, the sound appears to be coming from inside and is not related to the suspension or wheel-bearing. I am going to bring this to Mercedes to diagnose being that I am still under warranty; however, I wanted to pick your respective brains as to what you think this might be attributed to so that I can steer Mercedes in the right direction (no pun intended).

places

Lots of creaks in the w205. Many threads here on it. Do a quick search.

jb1894

Update: This morning I did discover this upon pushing down on the car. Makes me think something is wrong with the passenger upper control arm. See attached.

lukeg310

I had similar problems with 2015 C300. I took it to the dealer where they put a lot of felt tape on the center console, behind the instrument cluster to help reduce the noise. I had to take it few times to Mercedes and the foreman actually ended up removing the whole dashboard and put tape on pressure points. One thing I forgot to mention is also the belt buckle needed some felt strip so it wont rub on the seat and also they had to do some work on the passenger seat to make the noise go away. I have run flats and have been a blessing in LA due to the potholes.

jb1894

I forgot to update this this (apologies). It turned out to be a bent strut mount. The strut assembly was bouncing/rubbing against the strut mount due to not being properly seated. New strut mount and problem solved.

botaggs1

Glad you got it resolved. Was this an issue with the dealership's installation? Also, why did you have the front suspension components replaced initially? Asking because I am now paranoid and am hoping I don't run into this issue after my warranty expires!

jb1894

Prior to me buying this car, the independent dealership which I bought it from obtained it from a mb auction since the prior owner “drove it hard and put it away wet” so-to-speak. The car had 40k miles and while in great condition overall, the car needed to have significant wear and tear work performed. There were a couple noises originating from the suspension which prompted an inspection which revealed that many of the components needed to be replaced, and since suspension parts are generally replaced in pairs, it turned into a full replacement of the suspension.

The issue in my situation was that the independent dealership shop did a half-*** installation job and also did not replace the strut mounts (they failed to mention that fact) because their “interpretation” of what their obligations were did not require them to do so. I could not figure out what the noise was since I had assumed they had replaced the mounts, but after realizing the noise was not coming from the control arm but rather the strut mount rubbing against strut assembly due to the top center nut on the passenger side not being properly seated. I had the mount where the sound emanated replaced by my mechanic (at my cost so that the job was done right) and the problem was resolved.

front OEM strut mounts don’t cost much - little over $100. Should you have to replace them, you won’t break the bank.

fabbrisd1

You got off "lucky" make sure you go thru your MB again before you crossover 4yrs/50K miles and your new car warranty expires

jb1894

Appreciate the heads up. The car has been inspected by several different parties since then including Mercedes stealership as to ensure there are no other issues. No codes, recalls, electrical issues, AC, heating, etc. All the major components (brakes, tires, and suspension) were all replaced; however, the worn out struts mounts would not have been covered under a factory warranty as those are wear and tear items and not issues resulting from the factory or their original assembly of the car. The issue was just placing where that sound was coming from.