I can’t believe I didn’t come across this thread before. Thank you “cinca”
I have my 2012 300c since last May, and I know most new cars have some sort of rattling and cracking some come and go, and some remains. One of the reaming was the driver seat cracking sound. It doesn’t come all the time, but you hear it mostly when you accelerate from a stop or during stop and go traffic. even if you have the radio on you can hear it clear. It’s very annoying. sometimes when I have ppl in the car I forget what I want to say because of it. I tried many seat position, pushing various part of the seat, and let other ppl drive the car just to duplicate the sound but no luck, until one day I had enough of it. so I sat at the back seat of the driver and started to pull the head rest towards me then the creaking started. I guess the leather of the back seat meets the plastic of the head rest was the problem. I think the solution is simple and easy, but I didn’t have the time to get it to the dealer yet but now I know how to stop the creaking before it starts, just pull the head rest forward to losing it up