Exhaust Rattle C63S coupe.
 

Anyone else got it?
With the exhaust in "open" mode there is a distinct metallic rattle coming from the drivers side under a load that's driving me crazy. Sounds very much like the baffle or flapper in the exhaust is rattling around.
Anyone else having this issue? What did you do about it?
Haven't been to the dealer about it yet but will take it up on the first service.

Yes it is a problem :( my Edition 1 has it and so far still waiting on MB and AMG engineering to send me new part, should be in end of March :((( annoying as hell the noise, but confirmed from MBUSA that i can drive it safely for now...

It started back in November and they replaced the Flap once already and lubricated is twice!!!it docent work, Its under warranty and they will fix it that i know for sure....

can you make a video please?

YESSSS, mine is doing the same thing. I'm hoping they still warranty it with my downpipes on but we will see...

it's very hard to do so even the dealer couldn't get it so they can send it to AMG

I don't have a W205 but when I had rattling in my exhausts (probably the valves), I took it to the dealer and it looks like there was a TSB out on it. They stocked the exhausts and swapped out the whole system for me same day.

Yes same issue. Been into the dealer once for a lubrication which did nothing. Going back again this week.

It seems to occur around 2500-3000rpms under acceleration and sounds like some flapping but not in a good way.

I had the same problem. The motors of the exhaust flaps are causing the rattle (hence why you only hear it when the perf. exhaust is activated). In the end they had to replace the entire exhaust system. Was not impressed as the car was 2 months old at the time but no rattling since then.

do you know which part they are replacing?

Its Not a definite yet since they don't have a solution, it could be the small section where flap is, last time it didn't work. But my service guy said it's a full front to back.

Replacing the flap or trying to repair the section where the flaps are won't work. they tried the same with mine. since your situation appears to be exactly what I went through I'd say your car needs a new exhaust like I mentioned earlier. It's not a big issue as its still under warranty :y

I've been having issues with the dealer replacing my exhuast for this rattle. Now, it seems like at times the flap is totally shut and my car is muted and other times fully open. Anyone have a copy of the TSB or can recommend a dealer in Socal (OC) that can help me?

Just to add my C63 has developed this issue lately. It comes in around 3k RPM, sounding like metallic castanets and drives me crazy. I've not raised it with my dealer yet as the car is soon due a service. Hopefully I can hold out until then.

Mine started rattling very recently immediately after my 3 year service. Haven't had the time to take it back yet.

Anybody have any luck with this or can provide specifics if it was fixed/replaced? I have taken to two dealer and they say its normal or can't replicate. Such MB/Dealer BS.

I haven't' been able to replicate it for the dealer either... but will need to before I install DP's for sure...

My rattle came back worse than ever and has been back to the dealer four times for this without success. They say they either can’t duplicate the rattle or can’t find anything wrong. So, at this point I think I’m going to have to insist that they replace the exhaust. I have a good relationship with my SA and the dealer so hopefully they’ll do something.

Just took my car to the dealership and drove with the mechanic to show him the issue. He immediately knew what it was and said it was a common problem on the GTS's... Sounded confident he could fix it since he knew exactly what the problem was. Will keep you guys updated. My rattle is best heard in Comfort Mode, PE ACTIVATED, 3rd gear, 2.5k RPM, foot down 50-75%... it only lasts through about 3-3.5k, so you have to let mechanic know exactly when to listen.

Exactly the same conditions mine is reproducible under. Will be interested in the solution, if any!

This is annoying af.. no one knows what the issue is. My dealer gave up and said its because of the secondary cat delete. Im at eurocharged now and I believe even they are about to put their hands up and say they have no idea what is causing it!

UPDATE: Looks like we have found the source of this hissing/rattle sound for my car at least. Went to Eurocharged and there wasnt anything wrong with the secondary cat delete. The exhaust valves are the culprit since the noise goes away as soon as I close the valves. I clearly never drive with the valves closed so never discovered this but called the dealership who refused to take a look at it blaming the cat delete and they will send me on a road test with their head technician so Im hoping now that they will take care of the issue.

Yeah, that's what my MB mechanic told me it was this morning... glad you confirmed it. I did tell him it only happens with the exhaust valves open. Good thing I am getting this taken care of before my DP's =D