I use to remember saying to myself "wow, this cabin is very quiet", meaning that I liked that I didn't hear much road or engine noise when driving.

Then, all of the sudden I stated to think that the noise level increased significantly.

Now I know its hard to "remember" a noise level accurately, and that new tires or road conditions and speed will all effect the noise level.

But I'm fairly confident that the cabin noise level has increased.

I remember thinking this after the lifters on my engine were serviced, but I am not positive that was the noise level change point.

So, basically, what I am asking is..... does anyone have any knowledge of the sound proofing that is on a 2012 300c? And if so, can you explain where all the items are located on the car (there are probably multiple points on the car that have this).

This way I can have the dealer check these spots and see if maybe they are missing for whatever reason because I really want to get the car back to being quiet and enjoyable like it was

Thank you for your time.

 

Don't discount 1 or more tires going bad.

 

Quality tires and regular rotations are a lot more important that people realize. I've driven SUV's that were just roaring, thinking that they had serious wheel bearing issues, and it was just the tires.