Happy New Year. To cut a long story short a man moved my car for me and as I stood by I heard a strange rattling sound. I asked him if he knew what it might be - I thought it might be my exhaust. He said it sounded like a loose heat shield but said that garages don't fix them nowadays they just pull them off. Is that true, or should I take my car to a garage. There was a post on here a few years ago where someone advised to leave them off because the screw holes rotted. Thank you

They shouldn't but they do. The material is one step up from a disposable BBQ and the screws and washers pull through. Some success can be had by fitting ever bigger stacks of bigger washers. Many remove the shield entirely with, apart from one isolated case, no reports of any bad side effects.

They are fitted for a purpose. My mates' dad bought a Focus that had had the heat shield taken off. On a trip to Weston the exhaust started to blow & burnt a hole in the plastic fuel tank - how it didn't catch fire I don't know.

I've removed mine many times after they've become a nuisance. I've never experienced any problems.

Whether or not a heat-shield can be safely discarded will depend on the location and equipment in close proximity to it. One thing will be certain though, somewhere something will be hotter than intended.

................and something will be colder than intended. Presuming we are all talking about the heat shield on the exhaust manifold. One of it's effects will be to keep the cat hot by shielding it from the airflow. This in theory should allow the ecu to sort out the fuelling earlier and keep the exhaust cleaner. This is why I have persisted with our shield - washer castles and all.

Same here. Mine is more hole than shield now


But my back box shield is gone, there was no way I could find to salvage it. The fixings had corroded too

The material is super soft and cheese like
As a result a Washer rubs through and leaves very little material to actually repair it

Often you find now - the fixing snap clean off due to the amount of water and salt they've been exposed to right now

Ziggy

If we're talking about the inlet heat shield the 8v engine is fine but I've seen 16v's burn their stock air box.

I suspect it's not abrasion that enlarges the holes, but galvanic corrosion. Galvanised washers used there rust in no time due to this and the elevated temperatures. Even stainless turns a funny colour on the exhaust manifold.

atom0007 said:

I suspect it's not abrasion that enlarges the holes, but galvanic corrosion. Galvanised washers used there rust in no time due to this and the elevated temperatures. Even stainless turns a funny colour on the exhaust manifold.

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My heat shield has thick aluminium? washers between the heat shield and the manifold which are part of of the heat shield.

Seems to me the holes do not get bigger but rather the big washer corrodes or melts away which in return reveals the hole in which the big aluminium washer was fitted.

Mine rattles away too, and given that it is a 16v and I don't want any Dali-esque melted engine parts, was thinking of replacing. I think you can still buy these shields but am concerned at how to actually unscrew the rather rusty bolts currently not holding the current shield in place?!

Any ideas? Pity no one has invented metal tie straps so could just tie them on to the manifold ...

there are metal tie straps

I had this issue, I used high tensile fencing wire to tie it down tight. Had no issues since. However, for those not wishing for the agricultural effect. It depends entirely on how rusted the bolts are.

miktre said:

I had this issue, I used high tensile fencing wire to tie it down tight. Had no issues since. However, for those not wishing for the agricultural effect. It depends entirely on how rusted the bolts are.

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getting the old bolts out.. Plusgas soaks over days..,

I did this - then used "penny-washers" to get the same bolts to effectively hold the foil shield again..,
nice + quiet


Charlie

It probably means the rear heat shield, between the back box and the fuel tank / car underbody.

If it's anything like my Brava, the corner bolts pull through and if the exhaust isn't quite aligned it can rattle, sometimes more when reversing.

It stops excess heat coming up through the cab floor- and also the cover for the gear cables under the gear stick is made of plastic..it shields that from the exhaust heat. The shields of those cables are plastic as well. I'd leave it attached...and yes it does rattle if one of the holes pulls through.