CLK55 exhaust/cat rattle & sports cats

[Abdul]

Hi guys,

I've had a slight rattle in my exhaust for a short while now after bottoming out on a speed bump which has recently gotten worse.

It's a metallic rattle that gets worse when the car has no load or when revs drop below 1k, ie full lock when stationary and in drive/reverse while parking and seems to be located around the front of the exhaust between the cats and the center resonator.

Either way, I will have the exhaust off to check it out next week and if in the worst event my cat's have disintegrated does anyone know if I can use sports cats (200/300 cell items) to replace my primary cats?

Any help would be appreciated.

Cheers,
Abdul

 

[Alps]

yes you can, just need a decent exhaust place to do it for you.

100 Cell cats are better and try and get metallic cats if budget allows.

 

[Abdul]

Thanks pal, can you recommend a reputable supplier? I've never had the pleasure of replacing cats before lol.

I called MB, £600 approx for left side precat and over £2,000 for the right side. :fail

Do you think they could be welded into the existing pipework or would that all need to be freshly fabricated? I think I might ditch my usual exhaust place for this one and head to Topgear in St Albans as they seem to come highly recommended.

 

[Alps]

I had mine doneon the c36 at Hayward and scott, I found a supplierfor the cats from the US, it was a few years ago though.

Give Acid a call at MSL, they can book you in and do the cats whilst you wait, he will be able to price up the work and supply the cats. EMP performance are also good if you dont want to drive too far out.

 

[Abdul]

I had mine doneon the c36 at Hayward and scott, I found a supplierfor the cats from the US, it was a few years ago though.

Give Acid a call at MSL, they can book you in and do the cats whilst you wait, he will be able to price up the work and supply the cats. EMP performance are also good if you dont want to drive too far out.

Cheers dude, forgot they do exhaust work!

 

[Howard]

I had this noise after bottoming out , thought it was the cats.

Got it in the air and it was the heat shield mounts gone letting the shield touch the exhaust and set up a rattling noise at low rpm. I just pulled the shield off and binned it.

Worth a look first.

 

[Abdul]

I had this noise after bottoming out , thought it was the cats.

Got it in the air and it was the heat shield mounts gone letting the shield touch the exhaust and set up a rattling noise at low rpm. I just pulled the shield off and binned it.

Worth a look first.

Thanks Howard,

Did have a poke when I had some exhaust work done recently and it seemed to be coming from inside the exhaust itself, we were tight for time though and so couldn't investigate further. I will check next week, thanks.

 

[SpoonJar]

I had the same problem, rattling cats. Turned out all four needed replacing.
I took my car to Profusion Customs in Colnbrook . Got them to a full exhaust from the manifolds back. Car now has a nice low rumble on idle building up to the full on American muscle car sound as the revs rise.

 

[m2287]

I had this noise after bottoming out , thought it was the cats.

Got it in the air and it was the heat shield mounts gone letting the shield touch the exhaust and set up a rattling noise at low rpm. I just pulled the shield off and binned it.

Worth a look first.

I had this also!

 

[Abdul]

I had the same problem, rattling cats. Turned out all four needed replacing.
I took my car to Profusion Customs in Colnbrook . Got them to a full exhaust from the manifolds back. Car now has a nice low rumble on idle building up to the full on American muscle car sound as the revs rise.

Hi pal,

If you don't mind my asking how much did that cost?

Also, what did the exhaust then consist of? Primary cats obviously but any silencers/mufflers?

 

[Vlad]

I'm assuming that the CLK55 has a similar design to the CLK320 in terms of CATS, ie the primary cats are in the downpipes and the secondary cats are the ones under the middle of the car. I had a rattling on my 320 which was from one of the secondary cats. As the car had passed its MOT with very low emissions I had the cat cut open, the cat insert removed and then had the empty cat welded up again. Retested for emissions just out of interest and there was virtually no difference in the reading.

Another thing you can do, if the insert is lose in the secondary cat, is to put a trolley jack under the cat and slowly crank the jack up until it squashes the exhaust and jams the cat between the upper and underside of the metal skin on the exhaust containing the cat. Have the car running and once it stops the rattle let the jack down. By taking it slowly you avoid breaking up the cat honeycomb and to all intents and purposes its business as usual after that.

ps: The cat insert in my exhaust was completely intact when I took it out and it had not broken up