drdiesel52

Anybody know what this does and what it's official part name is? It rattles all the time and nobody in the MB parts departments knows what I'm describing and I want to silence / remove / replace it. It is on the exhaust right behind the rear muffler on the tailpipe.

DaveW68

Looks like a rubber muffler mount/hanger. Try spraying some WD40 or other lubricant all over it and see if the noise disappears or lessens.

drdiesel52

Its not a rubber mount. It has a steel tube that connects the back into the exhaust and a rubber hose that goes somewhere under the trunk. Maybe something to add exhaust noise to the cabin? I know some other vehicles have this, but I can't find any reference for the 2012 S550.

boardboy330

Hose going to the charcoal canister so condensation doesn't sit in the muffler?

alx

what year is your 550

drdiesel52

Its a 2012 with sport package. Actually, I just found out what it is by using a flexible camera scope. It is a vacuum diaphragm that controls a flap in one of the tail pipes that opens in sport mode. Apparently, this is on the 2014 Coupe, but I've not seen any reference to it on the 2012 sedan. Now i'll try to stop the rattle (probably the flap oscillating).

Thanks to everyone for your replies.