Rattling heat shield

[luckyboy984]

I'm sure some of you have had this problem with your heat shield covering the cat in the mid-section of the undercarriage. The rattling sound has been bugging me for months since I got it, and last weekend while putting on my summer wheels, we decided to check it out. We didn't really know what it was so we began unclamping the metal folds around it, guessed it was the cat underneath, and had to re-clamp it. We tried using some wires to secure it to keep it from shifting around (thus rattling) but i seem to have made the sound worse.

Before it would only rattle between 2k-2.5k RPMS not it does on idle and at other rpms/speeds. Anyone have a good trick to secure it in place? Thanks in advance.

[ZeroG]

I'm sure some of you have had this problem with your heat shield covering the cat in the mid-section of the undercarriage. The rattling sound has been bugging me for months since I got it, and last weekend while putting on my summer wheels, we decided to check it out. We didn't really know what it was so we began unclamping the metal folds around it, guessed it was the cat underneath, and had to re-clamp it. We tried using some wires to secure it to keep it from shifting around (thus rattling) but i seem to have made the sound worse.

Before it would only rattle between 2k-2.5k RPMS not it does on idle and at other rpms/speeds. Anyone have a good trick to secure it in place? Thanks in advance.

Most of the hest shields on the E36 cars were like a metal covering vs. a plate that is bolted up. I am thinking that it is detonation that you are hearing in the low load sections.

-Chad

[socal318ti]

The heat shield in my car is what looks to be some flimsy tinfoil just moulded to the underside of my car around the cat. I however got those same noises that your describing in the low RPM ranges. In my case it seemed that replacing the cat solved the issue; it seemed to have broken up on the inside. Hope that helps.

[schussey]

that ripped off of my car somehow.....it was terrible :(

-chris

[BMWVW]

I had the same problem. Both the catalyst cover and the heat shield between the fuel tank and exhaust were rattling.

Rather than buy a new shield, my mechanic re-bolted it with larger washers to keep it in place.

For the catalyst, it looked like he wedged a nut between the two pieces of shield around the catalyst to keep it more rigid. It has definitely helped.

Not the most elegant solution, but it has worked a charm on my car.
Cheers,
Paul.

[H3_2.1-ti]

I kept hitting it while creeping over speed bumps in parking lots until it also decided to start rattling. SOLUTION: wire snips. I proceeded to cut it off and sprayed a coat of high temperature paint on the cat.

cheers,

[m44ic]

yeah I ripped all that crap out when I changed my clutch :biggrin:

[cali-ti]

i need to resecure mine ... again. what is the purpose of this cheap little p.o.s. anyway? to keep things away from the potentially very hot cat? that's my guess so i don't really want to eliminate it completely. although, if it keeps rattling after another attempt to secure it, it may just go into the trash pile.

[LN318TI]

ya you need to put it on a jack and look at it mine came lose because the screw hole rusted a little bit but I just put a washer and a new screw in and it was good as new.

[aceyx]

your exhaust actually needs to be hot to operate correctly, especially the cat.

since there's quite a bit of air flowing underneath the car, the engineers needed a way to keep the cat at the right temperature to burn off excess fuel in the exhaust gas. it also helps to speed up the velocity of the exiting gas.

you can remove it and use the fiberglass wrap or whatever, or just remove it. you may experience a drop in gas mileage or power without it. if you live a cold part of the country, it's more important you do something to keep the heat around the exhaust than if you live in a warm part of the country.

[luckyboy984]

thanks guys. i'm going to think about checking the stealership for a new cover, it should be cheap since it just two plates of metal. if that doesnt work, i'll have to try bolting it down, or securing it better with the wire. There are two slots in the undercarriage cover towards the back of the cat. i'm thinking of getting some stronger wire/straps to run through the slots, but i don't know what i'm going to do about the front.

[JPerfect]

Mine was dragging underneath my car... or well half of it was, so i spent about an hour in my friend's driveway with a screwdriver and pliers ripping the rest of it off. The car was off for about three hours, and that thing was still hot. When I finally got it off, me and the ground i layed on were covered in rust and soot. The fiberglass stuff was orange from rust, and the aluminum metal cover was mangled.