Noisy Cat

[Robboc180]

Fitted a used MB cat today but is noisy on hard accelaration the garage noticed there was no O-Ring between the cat and the joining part of the exhaust towards the rear of the car, would this make a noise with the O-RING missing.

Grateful of any help.

 

[paulcallender]

What's the engine & chassis number? I'll look it up on the parts catalogue and see if there should be an O ring.

 

[Robboc180]

Hi, I've got the chassis number: WDB2020182F286457
Where is the engine number.

Thanks.

 

[Robboc180]

Hi, I've got the chassis number: WDB2020182F286457
Where is the engine number.

 

[paulcallender]

Ok it depends on the engine, I've assumed its a 4 cylinder petrol. The engine number is on the V5, its also on the engine but its dark outside LOL:

 

[Robboc180]

Ok going from your attachment it's the twin downpipe which looks like it need's the O-RING (olive), would this make a nosie if it was missing - i'm going to fit one when i get in from work to-day,

Thanks, will keep you posted.

 

[Robboc180]

Fitted O-RING today still noisy, can anything be done to the cat to remove anything loose inside the cat?

 

[paulcallender]

Is it just noisy, or is it blowing as well as noisy? If its blowing, then re-assemble with exhaust assembly putty or similar. If its plain old noisy, then either the cat you bought was faulty, or some other part of the exhaust is.

If the noisiness is metallic in nature, then it could be the exhaust striking the bodywork, missing rubber parts, etc. When I swapped the engine in my 280CE part of the job requires removing the exhaust system - and these little things were overlooked in the grand scheme of things.

 

[Robboc180]

Hi Paul - No it is not blowing, it sounds metallic as you say and starts around 2000 RPM and the sound is coming from the cat.

 

[paulcallender]

Does the noise occur when the vehicle is stationery, when its moving, or both? If its moving, does it occur if you coast with the engine off?

 

[Robboc180]

Noise only happens when moving under accelaration not coasting - think i bought a duff cat?

 

[paulcallender]

Its sounding that way. Did you hear the cat running on the car it was taken off? If not, then you cannot rule out, it being duff. And neither can the company who supplied it to you.

 

[Robboc180]

Noise happen's when under accelaration and not when coasting - think i've bought a duff cat?