[michaelreed]

Alright guys I need some help. I have what sounds like a loose heat shield or bad cat. It sometimes happens if i rev during idle and usually only happens at low rpm or going up hill lightly accelerating. I've been under my runner like 5 times and can't isolate where the sound is coming from. No heat shields appear to be coming off and I banged on the cats and nothing rattles. Anyone else have issues like this that they have resolved? Any other ideas on what it might be?

[TOY2G]

It is the heat shield that is wrapped around you cat on the exhaust manifold itself. Both if mine do it, and there is no good solution, other than replacing the manifold and cat. You can take a punch and put a few dents in the heat shield near the seam to help tighten it up, but I will end up rattling again.

[michaelreed]

Are you talking about the cats closest to the engine or the after cats? It appears I have a pacesetter on the passenger side because I only have one cat with a heat shield and it doesn't seem loose.

[Wuzzy]

I get the noise in drive at idle with the AC on. If I pop it into neutral the noise goes away.

[batcave4]

Mine fell off last week...at least the rattle is gone.

[WillK]

You could try a large hose clamp. I did that on another car I once had and it worked...

[ebg18t]

My center muffler heat shield was partially loose. Caused the same sound.

[michaelreed]

Originally Posted by batcave4

Mine fell off last week...at least the rattle is gone.

What fell off? Cat heat shield?

[SSt4r]

Check the heat shields ABOVE the exhaust. I've have them get loose and rattle. The corroded around the bolts; I had to add larger washers & that solved my problem.

[batcave4]

Originally Posted by michaelreed

What fell off? Cat heat shield?

Nah...muffler shield
, sorry for the confusion.

[michaelreed]

Originally Posted by SSt4r

Check the heat shields ABOVE the exhaust. I've have them get loose and rattle. The corroded around the bolts; I had to add larger washers & that solved my problem.

Checked all of them. None are loose or rusted off. The sound itself sounds more like the cat heat shield but its not loose. Could an exhaust leak cause this sort of noise? On occasion when I turn the 4runner on after its cooled off I hear a ticking sound. So Im pretty sure I have a leak somewhere but I'm not sure if that and the thin metal rattle at low rpm are related.

[Slvr RnR]

I've had the exact same issue the past 3 weeks. I hear it during idle with the windows down and when driving slow over a bump. I've gone under with a rubber mallet with the car in drive and parking brake engaged (I know,`stupid) and nothing seems to be coming from the heat shields. I can hear the rattle when underneath and think I can localize it past the cat, possibly the headpipe or muffler. When I'm driving the exhaust in general doesn't sound quite right either.

Keeping an eye on this thread.


...I should also mention I have a aftermarket Gibson exhaust.

[WillK]

Disregard...

[RAIDN]

I had a rattle like this at one point, the heat shield above the muffler had come completely off and was resting on top of the muffler and rattling. It was too big to come out on its own, but I finally just pulled it out and it went away

[Rob4r]

and pad it with sticky foam - i had the sound and this stopped it