Exhaust heatshield rattle...?!?

[Anonymous]

Hi! I'm new to the site and sincerely apologise if i've missed anything that could've been found using the search facility, believe me, i tried!!!   s:shock: :shock: s:shock:  

I've just bought my '01 about a week ago, the [very small time] dealer I bough it off was meant to "tighten a nut on the heatshield" as it was rattling slightly when i took it for a test drive...   s:!: :!: s:!:  Only very slightly at idle (when warm), very noticeably when accelerating at about 2-2.2k rpm...  s:cry: :cry: s:cry:  

Anyway, I traded in a BMW 316i SE that was on the HPI list as a cat C total loss (but that had been repaired), and it had a couple of minor 'issues'  s:o s:o  , so a couple of days after I collect the 2, when it's become clear that he hasn't "tightened the nut" I take it to my usual garage (I didn't want to take it back to the [small time] dealer due to the 'issue' with the 316i  s:oops: :oops: s:oops:  ), and my usual mechanic, who's probably most used to working on Mondeo's and vectra's  s:shock: :shock: s:shock:  , suggests removing the heatshield and bending it so that it's in constant contact with the exhaust?? I thought the whole idea of the heatshield was that it was meant to keep heat away from the outside (and therefore, NOT touch/conduct heat from the exhaust!?)...

Also, someone at KwikFit (ok, ok, i just popped in on sunday afternoon to find out what they thought, ok!!!) thought that it'd be best to remove the offending loose nut and weld the thing in place??? is this right???

As you can probably guess, I haven't got much of a clue when it comes to cars!!!   s:oops: :oops: s:oops:  I know what I like them to look like, and how i like them to drive, but not really got a clue about how they work!! (gimme a PC to fix and I'm happy! but cars? I'm lost!!!)

Any help would be appreciated!  s:D s:D  
Cheers
James

[so.simple]

Here it is: http://www.mr2roc.org/phpBB2/viewtopic.php?t=5291&highlight=angle+grinder+rattle   s:D s:D

[MikeBoo]

Is this link still available as I get a 404 message and if it's no longer viewable which is the best topic to look at because I have the same heat shield rattle?

[normanh]

The lower heat shield nearest the manifold is welded on, the upper piece is supported by straps on the inside bolted to the lower shield, each subsequent shield is again supported by internal straps. The straps clamp around the pipe tight, a rattle usually occurs when one of the captive bolts rots through. A quick fix is to replace the offending bolt which my necessitate the removal of a strap, loosing one didnt affect mine and the rattle was cured. I got rid of all the shields when I had to replace the cat, removing them all can be the best cure sometimes.

Norman

[MikeBoo]

Thanks, if I can stomach getting under the car today in the sweltering heat I'm sure to find a variety of horrors (though it didn't seem too bad when I originally checked it over) especially after reading the recent posts and hopefully then I'll get to grips with the heat shield.

My first challenge will be getting the car jacked up as it's been lowered by the previous owner and it was significantly lower than others I saw whilst on my new car hunt and my trolley jack is >20 years old and a cheap hobbyists one at that, so not a low profile one, or one that raises particularly high.
Then the second challenge will be to remove the nappy.

[normanh]

I am like you Mike, in my advancing years I have a much bigger profile in the middle now days. Caution if using a trolley jack always use an axle stand for safety. The nappy is easy to drop to give access - plastic fixings on the back bumper a a number of short bolts in captive nuts if they havent already been sheared off, I have used cable ties in a couple of places.

Norman

[Gaz mr-s]

Some people use a large jubilee clip to clamp it.

[Topdownman]

My cat heat shield has completely corroded bolts and moved quite a lot by hand when I tried it. I have done a fix using a length of builders band wrapped around, squeezed with pliers to get the holes lined up and then an m6 bolt through it to tighten it up. Doesnt look particularly pretty but the rattle seems to have gone.

[Joesson]

Iirc the heat shield is in two sections, top and bottom and the two spot welded together. The parent metal seems to corrode around the weld and eventually it is heading for two separate sections again.
When I decatted my OE exhaust manifold I also fixed the annoying rattle by drilling out the spot welds and replacing with stainless machine screws, nuts and washers. I used a U shaped exhaust clamp at the flexy joint.

[normanh]

You cant clamp it tight unless the straps are still present as they support the shields around the actual pipe without them theres a huge gap. Once the welded shield is loose I reckon its going to be difficult.

Norman

[MikeBoo]

Well I had a look and found that the 2 halves were held by 2 bolts and some remnants of a 3rd, with all the others rusted away.
I'll see about buying some nuts & bolts to clamp this back together and see if that fixes it.

[BARNPOT2000]

You cant clamp it tight unless the straps are still present as they support the shields around the actual pipe without them theres a huge gap. Once the welded shield is loose I reckon its going to be difficult.

Norman

I have a similar rattle which I've isolated to the heat shield just below the flex pipes. Does anyone know roughly what size jubilee clip I should get and would two be needed please? Ive tried to measure but it's tricky to judge given the sheol tapers quite a lot, I'm thinking about 100mm or maybe bigger? If anyone has done the jubilee clip fix hope you can advise the best option🤞🤞🤞

[Carolyn]

I have a similar rattle which I've isolated to the heat shield just below the flex pipes. Does anyone know roughly what size jubilee clip I should get and would two be needed please? Ive tried to measure but it's tricky to judge given the sheol tapers quite a lot, I'm thinking about 100mm or maybe bigger? If anyone has done the jubilee clip fix hope you can advise the best option🤞🤞🤞

Put a piece of string round it.  It'll give you a good enough measurement for the jubilee clip method.

[BARNPOT2000]

So I've tried the jubilee clip idea, no success in removing the rattle but I did notice one of the studs had Rusted through so replaced that with a bolt. I spaced the gap between the two shield halves with a washer and still no joy still got the rattle 😵. Just wondering, can anyone tell me if there should be some sort of heat resistant spacer placed between the heat shield halves, what was there, if anything, originally or should they be pinched tight together metal on metal with a bolt?

[Joesson]

I fixed the two halves of the heat shield tightly together with machine screws and nuts, no packer/ gasket between the two.
There is an area at the front end where the shield meets the flexi, a weld typically breaks there. I cured that with ( can't remember if it was one or two pipes/ clips , but I used a conventional U shaped exhaust clamp/S.
Thats been fixed since I've had my car.

[BARNPOT2000]

I fixed the two halves of the heat shield tightly together with machine screws and nuts, no packer/ gasket between the two.
There is an area at the front end where the shield meets the flexi, a weld typically breaks there. I cured that with ( can't remember if it was one or two pipes/ clips , but I used a conventional U shaped exhaust clamp/S.
Thats been fixed since I've had my car.

Thanks @Joesson, I'll dive under again and try it without any spacers and take a closer look below the flex 👍.

[BARNPOT2000]

Latest conclusion from today's thumping shaking and general poking around is that my rattle is not heat shield related. It seems likely that the exit pipes in the large rear silencer box are vibrating and will need welding up. I've seen a thread somewhere where the box has major surgery and she's opened up to allow the welding. Does anyone know if there is a way to stabilise these internal pipes without cutting a large section out of the silencer??

[BARNPOT2000]

Hoorah! Exhaust rattle deleted. As suspected, back box exit pipes had cracked tack welds. A full circumferential weld inside the exit pipe stubs fixed the problem. The pleasant driving experience has returned 😊😊😊.

[BARNPOT2000]

Just for info this is a picture of the offending welds that had cracked causing the horrible rattle.