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[geoffr70]

Hello, my o/s cat converter is rattling. After hunting down and sorting the rest of the noises I am left with this!

Does anyone have any good (cheap) suggestions on how to stop it? I heard someone saying to crush it, but this doesn't sound right!

My car was nice and quiet after i did the o's exhaust manifold gasket, now this presents itself! Also, has anyone, considered it, or actually removed the cats, just replacing them for MOT? What pros and cons would there be? Thanks

[hoofing it]

When you say the cat rattles do you mean the heat shield or the cat it's self.
you can't remove  the cats if it has a lambda after the cat

[geoffr70]

Oh you've got me stumped now. I got it jacked up and got my head under there, it sounds like the cat I'm pretty sure, I had my head right on it. Although I had the heat shields off yday when i did my handbrake, could that be related? Thanks

[hoofing it]

if you hit the cat with your hand does it rattle inside the cat or does the heat shield around the cat rattle/loose.
if the cat rattles inside it its knacked.

[geoffr70]

I think it was defo the cat. I'll jack it up again tomorrow to double check. Where can you get new cats and how much are they? I didn't hit it, ikt was just rattling from the engine running.

[amba]

I had a very similar situation last December just before mot due.

My nearside cat developed a very noticable rattle and when you hit the underside of the cat with your hand it was like the inside was loose.

It appears that the "brick" becomes detached and this is possibly the same noise you have now got.I unfortunately went down the route of the quick fix and bought a "Speedy Tyre Fitup place" relacement and lambda sensor as needed to get mot passed.This it did but only after some very spirited driving before hand to get emmissions down to pass rate.

Since the cheapo cat has been on car it sound really nasty and have invested in a breaker sourced genuine GM cat to go back when I do the n/side manifold gasket.I am also hoping the noise will go and sound more like a proper V6.

My advise is replace cat but only with genuine VX unit,and due to costs of new,second hand is the best bet.

[geoffr70]

Thanks for that amba! How much was your 2nd hand cat if you don't mind me asking? I'm not being funny, but how can you trust that not to go the same way as your original duffed one?

I'm not bothered about emissions, as long as it passes its test and sounds quiet, like it should be! Thanks

[amba]

I paid £60=00 for my replacement which was 30% of what I wasted on the nasty after market thing .

I understand that as long as the insides don,t sound loose and rattle then the cat is probably ok for another fair few miles.

Suppose it is that age old gamble with buying second hand..but atleast it is a genuine item and chances are it will last .