4 replies to this topic

[2003 V8 TT]

Can someone please advise on the difference in sound between a rattling cat vs. a rattling heat shield on a V8? Better yet, can someone please post a picture of heat shields on a V8, so I know where they are?

I have a rattling sound -- sounds like marbles in a can -- and I'm thinking it's the $$$ cat that needs to be replaced. I'm going for aftermarket high-flow cats. But I don't want to spend the money if it's just the heat shields.

Thanks in advance!

[GKP]

Marbles in a can? I'd say you've just described the sound a knackered cat makes.

[TEAM MAG]

Agree, that sounds like a done CAT. If it were a heat shield, it would sound like a loud vibration at only certain RPM's.

If you are in the USA, the CAT should be covered under the emissions warranty on a 2003 V8.

[Günter]

there are small metal rings (those should hold the catalyst monolith in place) who sounds like marbles if the catalyst is fully hollowed out. Just undo your catalysts -shake them, an if it sound like sand running on a plate there is still some of the ceramic substance in it. Bud that 'powder' is useless for you. Look from behind or into the o2-sensor holes and try to get the rest of it out.
Than you will have *free flow* pipes

As others have said : The heat-shields on the exhaust manifolds are mostly bend and broken by the different heat behavior of the exhaust to heatshield material. So those will not exactly rattle like 'sand/marbles in a can'.


here you can see what i have done now on both sides, the small black metal rings are original. I have replaced the rest of the ceramic monolith with some internals of after market 'race type' metal catalysts .

just cut the end of OEM and universal-fit aftermarket parts off, reassemble it all and weld everything in place.

Edited by Günter, 17 March 2009 - 10:50 AM.

[2003 V8 TT]

Thank you very much!