Rear silencer heat shield broken - replace or leave off?

[Dracoro]

Toyota Avensis T27 2009 1.8 estate.

Noise when idling, so up on stands and took a look and the rear heat shield was just sitting on top of silencer (causing the loud rattle!). The bolts are there but the shield holes are now too big (either broken or still sitting under bolt) so fell off bolts!

Anyway, looks like I need to drop rear silencer and screw new heatshield on so looks simple.

HOWEVER, do I actually need to do this? Can I just run car without the heatshield? (now removed to stop noise!) as only do 2/3k a year in it. There’s a good 2 or 3 inches away from anything above it so not sure how much heat there would actually be or whether any harm is likely to happen. If I can live without it, that will save £50/100 (I guess cost of heatshield) as this is bangeronomics!

[Tyre Smoke]

Leave it off.

My TVR has two pipes running an inch below the fibreglass floor of the boot with no heat shielding.

You'll never have a problem.

[Dracoro]

I just thought of another 5p solution.

Some small bits of tin, drill holes in them. Attach tin to bolt (with heatshield in between of course!) to clamp the heatshield in place.

Not quite sure why I didn’t think of that in the first place

[Dracoro]

Tyre Smoke said:

Leave it off.

My TVR has two pipes running an inch below the fibreglass floor of the boot with no heat shielding.

You'll never have a problem.

Thanks! If my idea it too much of a faff (sure it won’t be) then good to know…

[Tyre Smoke]

Your solution sounds like a lot of crusty muck in your eye as you lie on your back swearing.

My approach to heatshields on 'cooking' cars is rip it off if it rattles.

Where are you and when do you plan to do the job? Can I come and watch with a cup of coffee?

[E-bmw]

Dracoro said:

I just thought of another 5p solution.

Some small bits of tin, drill holes in them. Attach tin to bolt (with heatshield in between of course!) to clamp the heatshield in place.

Not quite sure why I didn’t think of that in the first place

^^^^ This.

I have done exactly that so many times I can't possibly count.

Large washer, strip of aluminium, spare bit of pretty much anything resistant to heat will do it & it will likely take a few minutes when the car is in the air.

You don't even need to do them all if some are behind the actual silencer.

[LennyM1984]

An old beer can will work well here. Snip off the bottom bit, poke a hole in it, and hey presto, you can reattach your heatshield.

[Dracoro]

OK, now re-attached using some roofing lead I had in shed. Now done, I could easily replace those with tin but sure lead will be fine.

Only took an hour to do.

Pics below.

Those holes should be small for bolt but obv broke off..



Lead cut with holes



Silencer without heatshield



Silencer with heatshield re-attached



Couple of pics of attached bolts…




Result!

[911r]

I’m sure I’m wrong as I don’t know how hot a exhaust gets , but I used to melt lead air rifle pellets with a lighter when I was a child . So I hope those lead bits don’t melt . Don’t ask me why I did that when I was younger .

Edited by 911r on Saturday 2nd July 12:44

[Dracoro]

There’s a good inch or two of space between exhaust and heatshield.
Melting point of lead is something like 325 degrees C (which is higher than tin I think).
Silencers get to 150/250 deg celcius I think, so should be OK,

Regardless, new simple to remove and replace with tin/alternative if I notice those lead “washers” failing. Will keep on eye on them anyway…

[E-bmw]

Excellent job, will be fine.

[Perseverant]

I'd be inclined to take these shields off. My old 190e developed a sudden hideous clatter which was the shield on the propshaft! That was many years ago and hasn't been any problem. Also on our MX5, the shield under the boot floor is a useless bit of tin which simply gathers amazing quantities of dirt as an extra source of starting rust - not something desirable given its propensity to rust. I'm not sure if there were some rules and regulations which promoted fitting these shields, but I don't recall any older cars in my past having them.

[GreenV8S]

Perseverant said:

useless bit of tin

It's possible that it's there to protect the bodywork from excessive heat which would degrade the corrosion protection. Although the shield itself looks useless, it may be the reason why you still have a boot floor.

[E-bmw]

GreenV8S said:

Perseverant said:

useless bit of tin

It's possible that it's there to protect the bodywork from excessive heat which would degrade the corrosion protection. Although the shield itself looks useless, it may be the reason why you still have a boot floor.

^^^^ Wot 'e said.

These things are designed by people far more aware of the issues surrounding their use than you or I.