AP E63

Just wanted to know if this has been something noticed from other owners. I just recently picked up my C450 2 weeks ago and recently noticed that when I first start the car and also when I hit the gas a little hard there seems to be a rattling noise coming from the exhaust. As if something is loose and moving about under acceleration. Doesn't seem normal..

Thanks!
AP E63

cenzo86

Is this noticed during Sport + mode driving? If so, try driving faster and let off the gas before if upshifts. Do this over and over to fix the rattlong noise.

AP E63

I believe it was in Sport+, but I'll have to double check. Do you know what is causing the noise? Also, how does your above mentioned method fix it? I'm willing to try anything at this point

cenzo86

It sounds like the "controlled backfire" the folks at AMG wrote into the ecu code in Sport + mode. What you are hearing at low RPMs is a growling burble coming from the exhaust, not a rattle. Coming off the gas at higher RPMs causes a full blown 3 round burst like backfire. For maximum effect, drive through your local airport or any place with lots of off ramps and underpasses. Try it... you like!

AP E63

It's not the exhaust burble. The noise happens when I get ON the gas not when I get off the gas. It's very easy to distinguish from the controlled backfire. It sounds like a metallic banging noise. Going to check for loose bolts or something today. It's gotten pretty annoying now, louder than before.

Gungaslow

Check the heat shields and the exhaust hangers on the exhaust.. Somethings may be loose.. Usually if you get under the car and bang on the mufflers you will be able to hear what's rubbing