Rattling Cat? Can anyone help?

[Ele34]

I brought a 2nd hand Silver Mercerdes C class Elegance Estate a couple of months ago. I just love her she drives really well and looks great! I new when we brought her that the cat was rattling? It really got on my nerves so I took it into a tyre and exhaust centre and they put on another cat - but it came out sounding no better? We took it back again and they replaced it but it is still rattling? I am due to take it back this week does anyone have any suggestions as to what else it could be?...... Is it because they are not fitting genuine parts? I just wonder if they will turn round and say there is nothing more they can do? Where do I stand? Do I ask them to put back on the original Cat? Is that something they could do please help?

 

[rpe2]

It could be that the original cat had broken up, and the rattling noise that you can hear is the material of the old cat rattling around in the silencer further down the exhaust. If so there are 2 options:

1. replace the rest of the exhaust system

2. earplugs.

2a. Ask the garage to check that there are no broken brackets as these can sound as bad as a knackered cat.

Regards

Richard

 

[rpe2]

I brought a 2nd hand Silver Mercerdes C class Elegance Estate a couple of months ago. I just love her she drives really well and looks great! I new when we brought her that the cat was rattling? It really got on my nerves so I took it into a tyre and exhaust centre and they put on another cat - but it came out sounding no better? We took it back again and they replaced it but it is still rattling? I am due to take it back this week does anyone have any suggestions as to what else it could be?...... Is it because they are not fitting genuine parts? I just wonder if they will turn round and say there is nothing more they can do? Where do I stand? Do I ask them to put back on the original Cat? Is that something they could do please help?

... oh cheapie OEM cats generally (but not always) sound tinnier than the genuine parts [explains about 40% of the price difference].

 

[Dave Lewis]

If it's an actual rattle, as opposed to the nasty tinny sound a cheap cat makes, it could be the heat shield above the cat rattling on it's mounts. Give it a fiddle when the car has cooled down.

 

[GazCaff]

I'd say check the heat shield too.

 

[Alex Argent]

Are you sure that it's the cat that's rattling?

I had a similar noise a couple of years back and assumed it was the exhaust, although tbh it was more of a clonking noise than a rattle. Turned out to be broken rear suspension spring - quite a common problem on the W202/W203 I'm led to believe!

I agree that the heatshield is the prime suspect, however it may be also worth checking that nothing has come loose in the spare wheel well and is rattling around. It's amazing how these things can transmit noise back into the cabin.

Finally, check that the warning triangle is secure in its mounting - I'm not sure where this is in the estate because in the saloon its under the boot lid. These can work loose and cause similar sounds.

Hope you get it sorted!

Alex

 

[Ele34]

Rasping Cat......

Thanks for your help so far guys. However the rattle is def. coming from the new Cat and not the shield etc... It's rasping at 3000 rpm? Because we have had a new exhaust we know it can't be anything to-do with that? I guess I am going to have to ask for my money back and maybe go to the main dealer or stealer as I read in an earlier message! I just wanted to check before the exhaust centre turns round and says it is something enginey...... Don't want to be fobbed off and have to keep this noisey cat! Thanks for your help!

 

[Alps]

i would take it back to the place you had it replaced from, sounds like the new cat maybe defective (they may have dropped it)

 

[Ele34]

Well I would do but we brought the car 2nd hand and the guy pointed out the cat was rattling before we brought it! The famous exhaust centre which I'm prob not allowed to name have fitted two cats now and we are waiting to hear if they are going to approach the main dealer to satisfy their cutstomer? I have just heard they will put on a genuine mb cat but if the rattling is still there they will not do anymore? Fingers crossed!