02 C320 Engine Rattle????? Emissions warranty?
 

Hello All,

I’ve done a lot of searches on this problem but wondered if someone has had the same problem or knows what it could be. I’m getting a rattle noise coming from underneath the car from the back of the engine. You can hear the rattle when revving engine at low RPMs (mainly on deceleration). My wife drove the car today and it stalled on her and the check engine light came on. She was able to get it home (only 3 miles away) and now I’m trying to figure it out before I take it in.

I’ve read about the catalytic converter but this seems to be between the cat and the engine. The engine seems to run fine and it sounds like its coming from the emissions system. The car only has 58k miles on it. I’ve read about the emissions warranty lasting for 80,000 is this true? My standard warranty ended at 50,000.

Any help would be GREATLY appreciated!!

Yes, your car is covered under 8/80 for cats. It does sound like that could be what you're hearing, your car has 4 of them, 2 per side, with two of them being close to the engine in the downpipes. The other two are under the center of the car.

If they're really bad, you can test them yourself by tapping on them with a rubber mallet or similar tool. If its bad, it's going to rattle.

Well, that sounds like it. I hit the area just before the 2 pipes junction into one. I can hear something rolling around in there. (sounds metal and round?) Do you think this is a cat gone bad??

Also is it safe to drive like this?? My dealership is 45 miles away or should I have the car carried over to the dealer?

Thank you very much for your help!! I’m mechanical but not an expert by far with this car.

Yes, take it in, it's not going to hurt anything driving it there. The stalling issue might be related but be prepared for it not to be too if they want to charge checkout time.

Does this sound like a cat issue?

Yes.