Magnaflow cat. converter

Recently have experienced a tinny rattling sound under the Riv particularly at low speeds and when shifting the trans. Finally got under the car last night and found the problem.

I had a Magnaflow cat from Hogan Performance installed maybe 3 years ago along with their downpipe. The cat has a heat shield tack-welded to the top side of the cat. The rear tack welds had broken, allowing the shield to vibrate against the cat body, most noticeable at low speeds. In fact it had become quite annoying. My solution was 2 LS104 hose clamps (7"dia) placed around it and moderately tightened, don't want to pull the heat shield down flat.

I know some others here have used Hogan's cats, if you experience similar symptoms, it's a quick check to see if your heat shield has developed this problem, before spending money on a shop diagnosis. Clamps from Home Depot: $2/ea. They could be a bit shorter, needed about 20" circumference to do the job.

Nice catch. I had a very similar problem after installing SLP headers a few years back. In my case, the OEM heat shield on the underside of the car (where the cat resides) is riveted on, and became loose enough to vibrate. The solution involved bending the heat shield with pliers to induce some tension in the metal, relieving the noise.

And if a guy had a welder, it looks like it would be accessible to tack it in place again.

AA wrote:

Nice catch. I had a very similar problem after installing SLP headers a few years back. In my case, the OEM heat shield on the underside of the car (where the cat resides) is riveted on, and became loose enough to vibrate. The solution involved bending the heat shield with pliers to induce some tension in the metal, relieving the noise.

Solved a similar problem with a few fat "dollops" of exhaust cement to tack the back shield on where the rivets broke thru. Dollop was fat against the exhaust pipe, pressed thru the rivet hole with a smaller dollop on top (so as to hold the whole shebang in place once dry and later (from heat) cured. This was on a muffler.

Another alternative would be to remove heat shield but put selfadhesive heat shield material on the car's floorpan.

When I replaced my exhaust with a factory Parke Ave Ultra exhaust the cat was in a slightly different place. I used sheet aluminum to extend the front of the heat shield forward and held it in place with exhaust cement. Works fine, no rattles.