M276 exhaust rattle

[Deleted member 65149]

For a few months now I’ve had a rattle on my 2012 C350 petrol for a couple of minutes after starting and whilst manoeuvring, so low revs. I’ve been waiting for warmer weather to get out and under to have a good look, and today was perfect. Reaching out under the car whilst it was jacked up on one side I was able to detect a rattle when thumping the exhaust system with my hand near the middle box. But even with axle stands, I didn’t feel brave/stupid enough to climb right underneath to see exactly what was causing the rattle - hopefully just a loose bolt. Unless someone has a brilliant idea, I guess I’ll have to suffer the few minutes of rattle once a week when I go shopping and get a garage to check it out when they’re all open again.

 

[BlackC55]

A heat shield, loose bolt or a stone trapped is my guess.

 

[Deleted member 65149]

A heat shield, loose bolt or a stone trapped is my guess.

Thanks. The first two were my thoughts too. Hopefully a simple job but not one to tackle with the car on axle stands. I need to get it somewhere with a ramp. I just hope that if it’s a loose bolt it doesn’t fall out in the meantime.

 

[Deleted member 65149]

Solved. When the car was in for its service last week they spotted a crack in both pipes leading into the cat. With the pipes sliding into the cat they had become loose by the crack, hence the rattle. New parts from Mercedes £800 plus fitting. This morning I got the pipes welded up at a local small garage for £60 and now quiet as a dormouse again - except on the drive home when the lack of noise resulted in me heading too rapidly towards three figures!