xHypex

iTrader: (1)

After unbolting the cat a few times to work on my STS I think I may have created an exhaust leak. I heard rattling so I removed my ypipe and checked it, but because it is a Stillen I can't see into the actual flex section. There aren't any holes in the pipe itself or welds, but who knows about the flex section. I also had to reinstall the pipe without new crush rings because I didn't have any available.
So now I have a slight rattling at idle that is definitely from somewhere in the exhaust. My possiblities are a) the old crush rings rattling b) the gaskets between the ypipe and cat rattling, or c) loose honeycombs in my cat Has anyone had any problems with gaskets and such or can someone describe the sound of a bad cat? I was going to run at the track tomorrow, but now I think I'll probably wait.
-hype

Jeff92se

iTrader: (82)

I really don't think those things could make a rattle noise. The downpipe crush rings usually squash and then "stick" themselves inside the flange grooves. I worn out gasket might leak but probably would not rattle. You should see if the Y comes reall close to something else on the car. It could be hitting something. A leaky Y usually has some sooty marks on the flex section. A loose piece in the cat usually blows itself out the back of the exhaust unless is a fairly big piece. but again, it probably wouldn't rattle.

I have no suggestions other than checking for loose bolts and such. I have converted to ball joint flanges to eliminate the flange leakage problems

Mishmosh

iTrader: (3)

In that area, the usual causes of metallic banging/rattling is the Y-pipe hanger/bracket near the cat, and also the CAT heatshield (the one above). You should make sure that all the hangers are in good condition the whole way down the exhaust, too, because otherwise the exhaust may be out of place and bang up against something.

xHypex

iTrader: (1)

Never thought of that. The noise didn't start until after I took off my ypipe so it's probably that ypipe hanger. I don't have a top heat shield and the bottom heat shield is tight so that's not the problem
Thanks for the great advice like usual .
-hype