I thought my engine was running a bit hot…

[cyrus1971]

I really goofed up this time. Rattle from rear end of 996TT diagnosed as cracked turbo heat shields. Then one day the rattle stopped and I naively thought “that’s good the cracks must have widened and the rattles gone but the plates still in place”.

Simultaneously the engine ran +5 degrees C warmer.

I just washed the car and one of the heat shields had dropped off, resting loose sandwiched between bumper and exhaust.

There goes another £500 quid fixing it !

[Adam B]

wouldn't have happened in a manual

so as its topical would this be covered by an OPC warranty or is it wear and tear?

[cyrus1971]

:-)

wear and tear :-(

[Adam B]

damn

I hear about heat shields going regularly on here. Not fully knowing what they do except shield heat (!) why do they let go?

Is it deterioration over time due to constant heat and if so why make them from chocolate? Or is it vibration, rust, corrosion from miles of driving etc?

[Merritt]

Adam B said:

damn

....if so why make them from chocolate?

Its a new EU directive you know... BIODEGRADEABLE / GREEN etc

[verysideways]

Very thin metal going through lots of hot and cold cycles and getting wet everytime the rear wheels go through a puddle...
The heat shields usually rust around the bolts holes that attach them to the car.

[silver993tt]

Then why not make them out of stainless steel? Would not cost that much extra since they are quite small.

[verysideways]

Agreed - stainless would help a great deal, but maybe it's not as good as reflecting the heat? Dunno, i'm no metalurgist...

[nel]

Problem with making them in stainless (apart from the cost!) would galvanic corrosion. Effectively they would have to be electrically isolated from the mild steel mounting points or the differing material electro-potentials would cause accelerated local corrosion.

I think they're galvanised aren't they? In many ways best keeping them cheap and replacing as and when. Your figure of £500 was a joke I assume, or is that really what it costs?!?

[cyrus1971]

yup £500 + VAT was the cost I was told last time. I will go private though. Bloody simple job to do with he right tools.

I thought it was called autocatalytic corrosion or is it one and the same ?

C

[Adam B]

£588 for a piece of thin metal? Are you sure its not chocolate?

OPC parts prices extract the proverbial urine

[silver993tt]

I have been told that the rear bumper needs to come off (at least for my 993 turbo). Maybe it's mostly the cost for labour.

[iaint]

Something that comes up quite often in the Jap car community is having bits of shielding and ducting fabricated as one-off items as the mods tend to require bespoke solutions.

Would it be a sensible thing to replace the mild steel shields with carbon fibre ones? Doesn't usually cost F1 prices and the heat shield is as much to keep cold water off hot turbos. CF would be fine for a hot application likt this.

Kind of thing that would certinaly outlast the stock items...

[sportsandclassic]

Hi there the shields if they are the ones around the turbo chargers are about £25-00 each and a couple of hours to fit them on a car with sports exhaust system if it has standard system r=then you have to remove bumper and intercoolers would make job alot easier...i would change spark plugs while you were that deep in.