Rattle from underneath?

[a6jus]

I have developed a rattle underneath my C320, but only happens at 1500-2000 rpm when hot, can be heard when at idle or pulling away at slow speeds!
Anybody have any idea's of possible cause, solutions much appreciated

 

[mioba]

probably the cooling cover on the exhaust, rip it off....

 

[Blobcat]

Agree with the above, get underneath and check out the exhaust system. Most likely the heatshield over the cat or a bracket.

 

[television]

I am not as kind as the others and I think it will be the CAT in the bottom pipe. Have you driven or parked on long grass recently.


Malcolm

 

[tom7035]

I am not as kind as the others and I think it will be the CAT in the bottom pipe. Have you driven or parked on long grass recently.


Malcolm

Hi Malcolm.
I note you're using the 'long grass' syndrome regularly these days. Is long grass such a good heat conductor that it causes such rapid contraction of the metal cat. shell to crush the ceramics? I can't quite get my head round that, as I cant see grass being a heat/cold conductor at all! I'd have thought driving in the rain would be much worse in this respect. Or am I missing something here?

 

[Parrot of Doom]

I've got a bit of a rattle underneath mine as well, at idle speeds. Hope its not the cat, if it is it won't be replaced....

 

[television]

Hi Malcolm.
I note you're using the 'long grass' syndrome regularly these days. Is long grass such a good heat conductor that it causes such rapid contraction of the metal cat. shell to crush the ceramics? I can't quite get my head round that, as I cant see grass being a heat/cold conductor at all! I'd have thought driving in the rain would be much worse in this respect. Or am I missing something here?

Hello Tom, when mine went, it was in a little country lane,where I met this tractor, so I reversed back to an opening to a field while the tractor went by, from that point on I got my rattle.
It was while I was reading up on CATs that I came across the article about the grass, sure, I understand what you are saying, but in practice people do drive through quite long grass at summer fates and the like, even around the coast here there is a lot of grass parking. the grass is often damp as well. when I opened up my old cat the ceramic goes to powder if you touch it with you finger and these things are only a push fit. the stainless steel case is not a very heavy guage and would cool quickly driving through the grass as appossed to parking on one peice. Its a thought and very hard to prove, but it does make some sense to me, anyway.

Malcolm

 

[a6jus]

Hi
Thanks for opinions.

Have been unlucky again, I had the MAF sensor changed last week at the stealers only £240 + VAT + LABOUR sir, GREAT!!

This week the rattle has got worse, even though it had passed a MOT on emmisions two weeks ago, the stealers informed me of the news, I had feared and been warned of by Television!

The CAT has gone Sir, and it will need to be changed A.S.A.P as You may have broken bits sucked back into the engine then it will be a new 320 Engine as well Sir!!!!

How much you may ask??
Just £918 all in Sir!!!
Is that both Cats I replied?
No sir just one!!!, It will be same again if you want to replace them both at the same time!!!

How can a 5 year old, fmbsh car need nearley £2000 of what is only a third of a exhaust????

Any comments??

I'm Gutted!!! This car is becoming a joke, and may need to go back to a BMW or Audi

 

[television]

Now lets take this one piece at a time, there is the upper CAT and the lower CAT, its normally the lower cat that goes, any thought of it finding its way back into the engine is crap and rubbish, its impossible, so forget that. If someone can tell me how, I would love to know

MB are not alone in this problem, so changing your car will not help, the sad joke bit is the price charged for these things, in my normal life if making 5 units cost £5.00. 200 cost £3.00 and 50,000 the cost goes down to £1.00.what I am trying to say is that if small firms can make them for say £100 in small numbers, they hardly cost the manufacture anything

If you search the web for CAT's there are loads out there, they come in all shapes and sizes, a firm like Top gear or specialist exhaust firm could fit you one in for a fraction of the price, if you can find one with a mesh CAT like I have, it will never go again.

Malcolm

 

[Parrot of Doom]

Perhaps its the pre-cat, in which case you could probably rip it out and not bother replacing it? Main cat would need replacing though.

Just make sure the engine is warmed up when the MOT emmissions test is done

 

[a6jus]

There are two cats both underneath, side by side
Each one is fed by a single piece of pipe from either side of the V6.
I hope there are no more pre-cats as that could be 4 cats & £4000 Sir?

 

[television]

There are two cats both underneath, side by side
Each one is fed by a single piece of pipe from either side of the V6.
I hope there are no more pre-cats as that could be 4 cats & £4000 Sir?

There are normally little cats (pre) high up in the down pipe and a larger one in the bottom and they come as one, the price though is still stupid.

Malcolm

 

[C220GJS]

I think this is your exhaust system, looks like two cats on each downpipe.
http://www.detali.ru/cat/oem_mb2.as...GM=716.667&CT=F&cat=65F&SID=49&SGR=210&SGN=02.
Geo.