2000 SL500 rattle/noise under car - PeachParts Mercedes-Benz Forum

turbozeke418 · #1 07-18-2012, 11:21 PM

I have a 2000 SL500 and it has only 66,000 miles. Tonight I noticed a rattling noise coming from under the car. It comes and goes but starting to scare me. It's definitely not the engine and I don't think its the trans. The car shifts smoothly and effortlessly. The car seems to make the sound after I let off the accelerator or when you hit a bump. You can actually feel it when sitting on the passenger side of the car when your left foot is on the floor or leaning on the trans bump. It isn't suspension related either. Has anyone heard of this or something similar?

RadioTek · #2 07-19-2012, 12:25 PM

Just a wild guess from experience with another vehicle: Check to see if the heat shield of the catalytic converter has come loose. Possibly some other part of exhaust system.

I had something like that on my work truck, but there were "other" things wrong...: A bracket/connector between the transmission and 4WD transfer case had broken. I doubt that is your problem.

Scott

turbozeke418 · #3 07-19-2012, 11:31 PM

It definitely is coming from that area. I was under the car today but not completely. When I hit the Cat near the manifold I can hear a rattling around inside it. I don't thing its a shield. I'll know more tomorrow. Thank god that's all it is!!!

SunGuy · #4 07-20-2012, 10:32 AM

Quote:

Originally Posted by turbozeke418

It definitely is coming from that area. I was under the car today but not completely. When I hit the Cat near the manifold I can hear a rattling around inside it. I don't thing its a shield. I'll know more tomorrow. Thank god that's all it is!!!

Several months ago I had a very similar rattle sound coming from the driver's side cat of my '99. When diagnosed, my indy tech confirmed that the filament inside the cat had broken/cracked and would only get worse. The risk is if the filament material breaks off, it can clog the convertor, exhaust gas flow is stopped or inhibited...it gets worse from there.

I had the job done by my tech and it included replacing the driver side convertor and the passenger side too. The logic being if one side went, the other side can't be far behind. We used the MB replacement cats as they're a bolt-on install. Magnaflo makes a universal convertor for our car that is much less expensive, but needs to be welded in place. At the same time we replaced the forward O2 sensors on both sides. This is not an inexpensive job, but my indy is fair, honest, competent and thorough. A second opinion quote from Midas, was within $50 or so and they would install the MB parts if I bought them.

IMO, this could be a DIY job if you either have access to a lift or can otherwise get comfortably under the car. I had neither so it was open checkbook, fix problem. Good luck with yours-

turbozeke418 · #5 07-22-2012, 11:36 PM

Thank you so much for that! I had no idea you could just unbolt it and put the new one in if it was a MB cat? The exhaust still looks brand new. It doesn't even have the rusty look to the pipes that every car I've ever had in the past has had. I'll look into the price of them. If not I have a guy who "takes care of me" when I utilize him and if I buy the magnaflow, he'd just weld it in for me for prob $50-100. Thanks for the help!!