I have had the vehicle about 6 months and it seems to have had this issue the whole time. When idling at a stop light or whenever not moving, engine vibrations transmit into the cabin. The vibrations are not steady, its kind of like the engine RPMs are changing cause the vibration will get better and worse but the tach is showing a steady idle. It doesnt matter which drive mode (Comfort, Sport, etc) it is in, the vibrations in the cabin happen in every mode.

We also have a 2020 GLC63 and there are no engine vibrations that can be felt in the cabin at idle.

Engine mounts? Take it to the dealer.

hey man - did you ever figure this out ? I have the same car same year with the same issue …

I never found out what caused the problem. At some point it was at the dealer for I believe the 10,000 mile service and after that I no longer had the issue. I am wondering if they either cleared a code that was causing a problem or did a software update from the manufacturer that made the problem go away?

great 👍🏼 thanks for the quick reply man. I’ll be taking her in to get it diagnosed

thanks again

Hope they find the actual Culprit, and that it's an easy fix.