Lerry

02 ws6 88k miles automatic.

hey hey guys im hoping you can help me out, i got this loud rattle/clank sound and im having trouble figuring out what it is. its it seems loudest when you lay on the ground by the passenger door. it also seems to have a "hollow" sound like its the sound is coming through the exhaust maybe? like a rock on a coffee can banging around. if you are under the hood you can hear it best towards the back of the engine on the passenger side but not as loudly as laying under the car by the passenger door.

the engine performance hasnt changed at all, i havent lost any pressure or power anywhere, no leaks. the sound is somewhat in sync with the engine while running idle but when you accelerate it kinda changes to a wild random knocking/clanking sound. the engine itself still sounds comepletely normal and doesnt miss a beat.

while driving when my foot is on the gas it tends to silence down to nothing but when i let off the gas and coast it rattles kinda hard then clams down to a minor rattle/clank.

im kinda lost on where to start looking first, any advice would be great..thanks!

sleepinghawk

Do you have headers? Have you checked your exhaust, right off the motor?

RJDio

If it's any loose exhaust pipe or fitting you will smell the raw exhaust down there with engine idling, I have cutouts and they leak like a ***** and stink up the place.

xenergyx

iTrader: (3)

mine did that after i went over a curb and cracked the weld that has the pipe go into the cat......does it do it at idle or is during acceleration or after a certain speed

Lerry

no headers , its all stock and i didnt smell anything coming out from down there.. it does it at idle and while im driving. if im doing around 20 mph and accelerate it will stop until i let off of the gas then it starts again. the sound seems the same in neutral, drive and park. the only time it seems to completely stop is during heavy acceleration.

"MAC"

iTrader: (1)

Id check the manifold bolts and the entire exhaust system on the passengers side some bolts could be loose.

nomasterase

iTrader: (4)

u hve adjustable panhard rod?they canbe noisey as hell when the jam nuts get loose

JDEP162

Maybe exhaust going over the rear end if hangers worn out

Nathan C

Is the cat converter bad?

'02crisisproject

Your lucky it makes the noise at idle, much easier to diagnose an annoying sound if you can climb around the car just sitting there. If you think it's the exhaust, I would jack up the passenger side when the car is cold, get underneath, and bang around on the exhaust with a rubber mallet or pound it with your hand(use a glove). You may be able to produce the sound and find out where or what it's coming from. If that doesn't work, start it up until it starts rattling, and climb back under the car. Push on different parts of the exhaust(with a thick glove) and see if the pressure stops the noise. That would more likely be a hanger, shield, or random bolt. Good luck!!!

Lerry

i got under the car and kinda pulled around on the pipes and nothing seemed to move, i didnt hear or feel anything loose... im wondering if i should take a video and try to capture the sound...it just confuses me because aside from the loud rattle the car drives as perfect as it ever has.

Lerry

im not sure how to check that.. if it was that would affect the cars performance right? ive had a bad cat in another car and it would drive like crap.

thetmeister05

Does it continue to do it after the engine has warmed up to temp?
Because I know a common "problem" with the LS's is the short piston skirts that almost sounds like a rod knock. When I first bought mine i was worried it had a bad rod, but it quieted down after it warmed up.
As far as I've ever noticed it doesn't COMPLETELY go away but from what you are describing it sounds really similar to what I initially thought.

Nathan C

To see if the converter is rattling you can tap in it with a rubber mallet. The converter in my daily driver has been rattling for about 5 months now and eventually the innards will clog up something and the car will suffer performance.
If you can take it to a shop and have them put it on a lift and see if they can tell you what the problem is.

Lerry

i took up to a local muffler shop and had them take a look, they guy told me my passnger side cat converter is bad, i dont know a lot about them but he said it sounds like part of it broke off inside and the noise im hearing is the peice inside flying around in there. he banged on it and i could hear something in there that sounded like it was bouncing around..
he quoted me 450$ to replace it and i cant really afford that right now so my next question is probably a stupid one but im going to ask it anyway lol... will it damage anything to keep driving it like this? im considering drilling it out and letting all the junk out of it until i can get another cat put on. i know that will hinder getting an inspection and make the car sound like and old beat up truck but from just a functional standpoint would it hurt anything?

Nathan C

It shouldn't hurt anything for a while, but eventually it will clog up something and then the car will lose power. I have the same situation with my 1998 dd Firebird. I plan on getting the cat gutted. You could also get it cut off and have a straight pipe welded in but that will throw a check engine light unless you have o2 simulators.

Nathan C

A GM tech also told me if you replace the converter with a universal fit converter, which is a lot cheaper, it still might trigger the check engine light because it's not as efficient as the OEM cat.

omarrakeen

iTrader: (2)

if you decided to keep the stock exhaust then simply buy a used cat from the classified..they go dirt cheap and you can do it your self. 450$ is ridiculous and i dont see why not buy a used cat. you really shouldnt waste money over the stock exhaust. get a used cat and do it your self. good luck!