rattling from exhaust (i helped myself -- you should to)

[chas]

this topic comes up fairly often. i finally have solved the rattling in my exhaust after a month or so. perhaps other can benefit.

so i had a strange rattle that only happened at a particular rpm at takeoff or at certain speeds on the highway. does rattle at idle. sometimes rattles when in reverse. got the vehicle hot and pulled up on the rhino ramps and tapped on the cat/exhaust pipes till i found a rattle. ok, the converter shield was a bit loose in the middle. bought a stainless steel band clamp and wrapped it around the middle where there isnt any crimping.

this reduced the problem some. after a little more driving it still there. after more banging, i decided it must be inside the cat. since i dont feel like a new cat i removed the o2 sensor after that cat on a hunch. the crimped connection the back of the o2 had some loss. i recrimped it and reinstalled.

ok, still rattling at speeds but much reduced. remove the o2 again, perhaps i didnt crimp it enough. nope a little ceramic bit was loose and rattling around inside. fine, i just replaced it wholesale.

ok, rattling gone. drive for a few weeks and the rattle is back. it would come and go though. very odd. it didnt seem repeatable. one morning when i started up to drive off it was rattling. turned off the engine and did a little tapping. the band clamp that connects the borla to the s-pipe on the converter was loose. but if the exaust slide forward a little (heavy braking) it would tighten and stop rattling. hard acceleration the exaust slides back a bit and it rattles. ok loosen band clamp, roughen the outside of the s-pipe a bit, overlap as much as possible and reinstalled band clamp.

quiet for two weeks. yes, these strange noise problems are hard to track down but have a bit of paitence.

[BadAzzRS]

Doy uo have a new cat or old? my cat has a good 80k miles on it, it makes a nasty sound when the car starts, and when i rev it.

[BadAzzRS]

is it like a heavy loud buzz sound? like ZZZRrrrrrrshhh? Thats what i got, its my cat alright

[Linxs]

Originally posted by BadAzzRS:
Doy uo have a new cat or old? my cat has a good 80k miles on it, it makes a nasty sound when the car starts, and when i rev it.

Sounds like that's your cat. I had to replace my cat around 85K.

[Tyler]

i just removed the whole heatshield from my cat.. no rattle..sounds sweet

[hockeyman]

Originally posted by Tyler:
i just removed the whole heatshield from my cat.. no rattle..sounds sweet

Re-welded the heatshield on mine, no rattles at all.

[chas]

82k miles (yes that's a little high for a '99 but i am probably going to give it the year off with the new truck).

the heat shield on the convertor is only crimped at the ends. the middle isnt crimped and has a strange flange that can easily vibrate against the body of the converter (its like they didnt extend the crimp and just trimmed off the excess).

[L32Projekt]

chas,

Thanks for giving me some ideas on where to start hunting for my very own personal rattle that seems to do exactly what was happening to you. Where's that darn thumbsup smiley when you need it?