Rattling From Exhaust/Heat Shield/Catalytic Converter?

[Blazing_Firebird]

I've had this problem since May, and after going to two different places, including a Pontiac garage, I'm going back to my dealer whom I bought this from (A good friend of my family) and having him and his mechanic fix this.

There's been a rattle on the car in the back near the exhaust that's very loud and vibrates whenever I start the car, take off in first, and shift into second. It's rather annoying, as I've never seen another F-Body do this before.

The Pontiac dealer switched me Catalytic Converters (mine was dead) on warrenty and they said they "fixed" the rattle, although it returned within a day.

One other looked at it, and said it was the heat shield, so they tightened it. Nothing.

Finally I went to my ex's dad (he words at a Ford dealership) and he thought it was the catalytic converter touching something causing it to vibrate, or something to that effect.

My question is, have any of you ever had a metal/metal vibration or rattle in your back end of your F-Body, I know Im not the only one that's had this problem, and how do I fix it...

[bouch3800]

checkin in with the same problem. i did all the same things as you and still havent gotten the **** fixed. no1 seems to "be able to fix it." i even had some people tell me the **** wasint vibrating. im personally asshamed of my pontiac dealer ship with the poor work.

[ellik]

ive got the same thing.... it started right after i added my dual exhausts. ive re-adjusted all my pipes esections to allow good clearance... that fices it a bit, ive cut the lower heat shield of the cat itself, that fixed another part of it. ive still got a little sgueek when im in drive but standing at a red light. embarrassing as hell. i think ive located it as being the heat sheild abov the rear axle. there are so many pieces of tin spliced together making up the heat sheild that its hard to find exactly whats loose and squeeking. Anyway, each thing that ive done has fixed part of the squeek, or a cetain pitch of the squeek, but theres more than one thing with a little bit of vibration in it contributing to the problem. good luck!!

[tommycat]

With stock exhaust:
I had two rattles. The first turned out that the exhaust had pulled away slightly from the catco and there was enough play between them to cause the rattle. Pushed them back together and had it welded and that one was fixed.

Now there is a faint sound on acceleration only when I just start the car on cool mornings. I haven't looked into it, but I figure it is along the same lines as the first. I expect it to go away when I put a new catback on.

[ August 20, 2003: Message edited by: tommycat ]</p>

[ellik]

expect to get MORE rattles by putting a high performance cat back on, not less. theres more vibration in the pipes themselves and causes things to begin to "squeek"

[darkthoughts5000]

when i had my edelbrock cat back "bolted" on and catco high flow cat welded on, rattling ocurred at idle, then rose up through the RPMs. very loud, very annoying! then i went to an exhaust shop with new magnaflow cat (old one was dead already), flowmaster muffler (edelbrock muffler died as well :mad: ) and also had them weld up all the seems. they also fixed my over-axel pipe cuz it was the wrong angle and threw on some chrome tips as well. no more rattles, leaks, or wierd faces from other people on the street.

[StegsRide]

yea i just put my exhaust on and its rattling at idle which is really embarrassing at stop lights. ive tried tightning so many things but cant seem to locate it. it is really annoying though :mad:
good luck fixing it.

[Everglades W68]

My car developed a rattle from the cat. Dealer replaced the cat under warranty.

[David Blalock]

I've got a rattle at idle, in park and drive and when I'm coasting in drive. It started not long ago and it's not too bad, so I'll just deal with it. Hopefully I won't have the firebird much longer anyway.

On a related note, on one of the Dodge Dakota forums I was on, (when I needed a truck, now I'm getting a camaro after high school), someone had a rattle coming from the transmission area, took it in and found that a torque convertor bolt had backed out and was causing the problem.

[F1GT]

I've developed a rattle on my aftermarket universal GM cat that I got from December. I went under, hit the exhaust with my fist and heard it was from my cat, I went under with a rag. Stuffed the rag between the Cat and the Cat's shield and hit it again and BAM, found the rattle. Turns out the weld on the shield broke. Put some putty thing that hardens within 15 mins into steel and fixed it.


Another thing that happened b4 I got this aftermarket cat was the stock one. The insides of the cat was breaking and clogging my exhaust up, I wait several months b4 fixing it. By that time, i could hardly accelerate and some of the pieces of the honeycomb went into the muffler!!!

Go under and hit the muffler with ur fist and locate that rattle. If you think its the shield and u've already tightened it, you can apply some silicone between the shield and floor panel to absorb the vibrations. I put some silicone on the above mentioned cat shield as a temporary fix to shut the vibration up until I can get some JB Weld or the like. When I peeled the silicone out, it was just fine, not burnt or anything.

good luck