Leak In The Cat.

Not so much a blazer question but hopefully someone can help. I just replaced the cat on my 96, and now it sounds like there is a leak there. I got under and it sounds like it is coming from the front of the cat where it connects to the pipe, but when I felt around I could not feel any air coming from the cat. So I am wondering if it might be a bunch of smal leaks, or is it just how the new cat sounds. Any help would be appreciated. Thanks

Did you disconnect any of the three-bolt plates that join some of the exhaust pipes together? Sometimes the bolts/nuts, and certainly never are the silver-metal looking gaskets between them are resuable. I had to replace a few of those gaskets, especially in the rear input pipe into the muffler when I re-did my pipework. And because I shook and juggled a lot of the stuff in front of the catalyst, had to replace the gaskets in the downtubes from the exhaust collectors too. It made this awful tickity-pop noises at idle and turned into a solid *SSSSSSSSHHHHHHHHH* when mashing on the gas. The only other thought that comes to mind is that if you purchased a "Universal fit" catalytic convertor, there is an air injection tube on one side. On my Blazer, such a tube would not be used because of the engine management and fuel injection with a complete lack of A.I.R. injection system to pump fresh O2 into the exhaust stream. However, if it came uncapped, it would also make the noise you are describing. Screwing a bolt into that small side tube will silence her right up.

Take it back to where you got it installed.

That is their problem.

It shouldn't leak at all.