Darth Cypher

Ok, I have an exhaust rattle in the rear of my exhaust. This happens at Idle and when I give it a little gas like when I start to move from a stop. It usually happens after the car warms up a little. When it did it today when I got to work (about a 5-10 minute drive), it started to do the rattle. It was still doing it when I parked my car so I got out and tried to pin point it before I shut it off.

It is coming from the right rear area. Nothing was hitting on the car as far as I could see. The hangers kept the catback from hitting the car. I laid on the floor to listen to the catalytic converter, I didn't hear anything from that. I guess I will try to jack it up this weekend and see if anything is loose or tap on the exhaust to see if anything rattles.

I originally suspected the cat but as I said, it didn't sound like the rattle was coming from there. Anything else I need to check out when I raise the back of it up and check around? Thanks.

babbage1109

iTrader: (11)

Could be from inside the mufler

andrewss

iTrader: (1)

check the mount just above the rear axle, mine used to viberate at a stop sign or sitting at idle.the bracket was broken off on one side, I welded it up on the car , no more racket.

strokerrace

iTrader: (8)

My heatshieldon the bottom of the gas tank is the source of that same problem. All the screws are tight and in it, I think I just might have to put some of that heat tape/sound deadener on the top of it and that should fix it...

Darth Cypher

It's up on ramps. I got under there and banged around and was able to reproduce the sound. It's not hitting anything. I inspect further up the system to the back of the Y-pipe and the front of the catback pipe that connects to the back of the Y-pipe is able to slide back and forth very easy. The clamp is tight on there though. I got the nut soaking so I can see if I can tighten it some more or not but somehow I don't think I will be able to. I think the pipe on the front of the GMMG is a little too big.

EDIT: If I can't tighten the clamp anymore, what fix can I do to keep it from moving? I do not want to weld anything.

Darth Cypher

Was able to tighten the clamp relatively easy. I hit the exhaust with my hand and the rattle that I reproduced earlier went away. I'll verify for sure when I drive my car to work tomorrow. All other hangers and clamps were already tight so I hope this is it.

babbage1109

iTrader: (11)

If it doesn't work just get it welded together

Darth Cypher

So far, so good. Heard nothing so far. I probably could have tightened it even more, but I don't want to squash the GMMG pipe down too much. I know there are tube expanders to put it back in it's original diameter. Eventually, I will put headers and probably some sort of I-pipe (to help with rasp) down the road. Thanks everybody (yet again), for the help.

Darth Cypher

Well this damn rattle came back anyhow. I guess it's back up on the jacks it goes. Thing is, when it was up there before, I found nothing else loose. The heatshield on the tank was secure. I'll check the cats again. Someone said it might be my muffler. I have a GMMG, I thought it had a "muffler" instead of a standard muffler. Would the GMMG muffler still have a defect like a regular one? I hope not because I like my catback as it is. Also, if I remember correctly, wasn't it a solid piece on there or welded on? If so, I don't want to **** it up nor replace the whole thing.

Oh yeah, in case anyone is thinking "Why the **** doesn't he just go and LOOK?"...I'm at work right now and not driving the Z. I might not get to it until this weekend.

joecar

I found my rattle to be the y-pipe fitting too loose in the i-pipe even tho the clamp is tight (it rattled during driving, and the i-pipe slid back/forth easily);

I used an exhaust pipe expander to slightly expand the end of the y-pipe so it fits more snug in the i-pipe;

also, need to replace the motor mounts to limit exhaust pipe movement, this is what causes the end of the y-pipe/i-pipe interface to get loose.

Darth Cypher

That's where I initially found the rattle sound. I tightened it up and it fixed it for a while though it still had some play. I'll see if it loosened up or something. I'll try the expander on the y-pipe idea. Can you put the expander on the y-pipe with it still installed on the car or do I have to remove the y-pipe to get it done?

joecar

You put the expander inside the y-pipe (so you have to drop the y-pipe)... then you turn the hex with a long handled ratchet.

2-1/8"-3-1/2" Exhaust Tail Pipe Expander

the expander's upper limit must be greater than the diameter of the y-pipe (which is 2.75");

most part stores have them for loaning out.