nopepper

I just bought a 1999 clk 430. When i pull out of park i notice a rattling noise coming from underneath as im accelerating it continues but eventully tapers off. It will start to rattle again after stops but not every tim.

Any ideas what this may be guys?

SRLyon

... catalytic converter might be the cause. I had a rattle/buzz on my 2001, dealer replaced it under the 8 yr emmisions warranty. Steve

nopepper

so it should be covered under my original warranty?

viguera

Depends on the mileage... ask the dealer.

If not, it's pricey... front is $400 and change, rear is $900+ (I know, my rear went out and was replaced not that long ago).

jtbeche

I had the exact same thing. It was just the heat shield on the cat. The cat itself didn't need to be replaced. I had it in to take the resonator off anyway so the guy just welded it back in a few places and presto...no more rattle. Not everything is as complicated as it seems.

viguera

That's why you ask them for the old parts if you're not sure...

patrick39

it maybe the heat sink is loose.... so try to jack up the car to see (plz remember use safety stands and NEVER go under the car with factory jack).

King320

Most likely the cat, just had them replaced on the ML last month because of the same problem.

oneofayykind

Where is the heat sink located? I am getting rattling noises under the car while idle and when it first starts accelerating then diminishes. Need to figure this out and don't want to spend a fortune to fix it.

Also I read somewhere that these are under warranty for 80k miles...what if you purchased the car used? Even though I dont have a warranty are the parts still warrantied?

rsnpride

Most likely its the catalyic converters. When I just bought my CLK, it also had the rattling noises. I replaced the catalyic converters and that solved the problem.

oneofayykind

how much does those run? I have a mechanic so I dont need to take it to mb dealer.

dennism13

Just had mine replaced yesterday. Rattling mostly when cold. Felt some odd idling too. Now purrs like it was new. Replaced under warranty.

zdfun

I am having the same problem right now, and looking for the best solution.

I have 2002 CLK 320, and confirmed that is the Cat Converter.

People told me to go to muffler shop to replace the aftermarket converters.

I have called the dealer, the whole thing is $900+, plus $230 labor. So your cost is around $1100, $1000 if you go to do it from other shop.

However, I think each aftermarket converter is around $250, but we have 2 converters. So the price for the aftermarket is around $500.

The different is around $500-$600, but you get an original brand new converters which contains 4 new converters (2 front, and 2 middle) with pipe.

I will go for the original one right now, but I will go to muffler shop to check if there is any cheaper deal tomorrow.

By the way, 8y/80000 is the warranty of your cat. converter.