How to stop exhaust heat shield rattles.

[aclwalker 3]

Due to the popularity of my "boot rattle" thread (http://the-corrado.net/.archive/forum/viewtopic.php?f=19&t=74319), I thought I'd write about another great noise problem with Corrados. This won't be news to old hands but I'm sure some people will find it interesting.

 

The main cause of heat shield rattling is simple. The clips that hold them on have corroded and fallen off, allowing the heat shield(s) to flap around in the wind and when going over bumps, causing quite a loud and annoying noise. Some people say "Just rip the heat shields off.", but I think that's terrible advice. They are there for a reason and if excessive heat gets to the bodywork then it accelerates corrosion for a start, heat speeding up reactions and all that. It could quite possibly also damage rubber components. I also know for a fact that some of the brake lines go under heat shields and if these shields were missing then you could be spot heating brake fluid at those points, which is probably not good.

 

Luckily the solution is actually really simple and virtually free, assuming your heat shields haven't been binned by a previous owner. I was lucky to have all of mine intact (I think). When I got the car they fair rattled about, but this was one of the first fixes I did about 6 years ago and it's still perfect now.

 

You need to go to the dealer and buy these clips:

Heat shield clip.JPG[/attachment:2k1ld32q]

 

Sorry, I haven't got the part number to hand. They are really cheap. I think they were around 20p each when I got them, so I bought 10 or so.

 

Simply go under the car (using axle stands of course, NOT just a jack) and locate each heat shield and look for missing or damaged clips. Simply push the new clips on with a socket and if necessary, push the central fingers on tight with a thin screwdriver.

 

Problem solved.

 

You may be unlucky and have a hole in a heat shield that is bigger than the clip, meaning it won't hold. In this case you can snip out a piece of metal sheeting (I used scrap tin-style flashing from a garage roof I think), which will cover the hole and then put the clip over that.

 

Your heat shields will stay solid and not rattle again for years.

[coolrado 0]

the advice of removing the heatshield is for the steel heatshield under the cat not the aluminium ones above it, the brackets that hold the steel heat shield on to the cat tend to break with the constant hot/cold cycle and they either start to vibrate making a really annoying noise, or it falls off completely.

 

the cat heat shield doesnt really do much apart from maybe stop the cat setting fire to long dry grass, or impact from stones, although the corrado uses a coated metal catalyst rather than ceramic so its quite tough.

 

but yeah removing the aluminium heatshields from the underside is a very bad idea, as you say.

 

also screwfix do some large stainless repair washers that are ideal if the hole in the heatshield is too big.

[aclwalker 3]

the advice of removing the heatshield is for the steel heatshield under the cat not the aluminium ones above it, the brackets that hold the steel heat shield on to the cat tend to break with the constant hot/cold cycle and they either start to vibrate making a really annoying noise, or it falls off completely.

 

the cat heat shield doesnt really do much apart from maybe stop the cat setting fire to long dry grass, or impact from stones, although the corrado uses a coated metal catalyst rather than ceramic so its quite tough.

 

but yeah removing the aluminium heatshields from the underside is a very bad idea, as you say.

 

also screwfix do some large stainless repair washers that are ideal if the hole in the heatshield is too big.

Yeah, I had to remove the CAT heat shield because the welds actually broke and it was vibrating. I'm sure I've seen some people say to just remove the other heat shields too, but it doesn't really matter, that IS a bad idea anyway, as we all agree!

 

Glad to hear it's a metal rather than ceramic catalyst. Is this the case for all catalysed Corrados?

[coolrado 0]

As far as i know the OEM one's are all metal, i have seen the inside of an early G60 cat and a 1995 VR cat and they where both metal, which is probably why they all seem to last so long.

[davidwort 0]

..the cat heat shield doesnt really do much apart from maybe stop the cat setting fire to long dry grass

 

that's not what I've always understood, it's not so much to shield things from the CAT as to shield the CAT from 'things', specifically water, the CAT gets vey hot in operation and spraying it with large amounts of water, say when hitting a large puddle would rapidly cool it and potentially cause damage or at the very least drop it below operating temp.

[coolrado 0]

the ceramic cats dont like being splashed as it can cause them to shatter internally but the metal ones should be fine, the heat shield wouldnt really stop much of the water anyway as they are full of slots.

[VR-OOM 0]

When the brackets broke on my shield I went out and purchased some realy long jubilee clips, think I eventually joined two together, then I ran it over the cat and down through the vents on the shield and tightened it up as tight as possible, rattle sorted.

 

James