Ok, so my mechanic put in my cattman headers a couple weeks ago, and I've been hearing a rattle when I get on the throttle. When in neutral revving it, I can hear it just as I push the gas pedal in quickly, then again just as I let off the gas pedal. I hear it also when moving when I'm on the throttle at lower rpms, but not all the time. All the bolts were tightened on the install, and I'm going again tomorrow for a check-up. However, I did notice that on the front header, that the gasket is kinda loose. There's a little space between the gasket and the head/header, and I can actually move the gasket back and forth with a screwdriver. It's not supposed to be that loose is it?

I was playing with the gasket before we put the headers on, and the sound I hear is very similar to the sound that gasket might be making when hitting metal. If the bolts are tight and that space is still there, what can we do? When this other guy put my y-pipe on my 01 max, he used some kind of light grey gunk that he put between all the connections to take care of any exhaust leaks... anybody ever heard of this stuff, or would it fix my problem? Thanx.
-Chris

 

Id loosen up the bolts on both sides of front loose header,adjust it,and tighten back up.
Exhaust has some play to adjust.

 

My b-pipe was also rubbing a heat shield.Had to bend the shield back some.

 

That's normal, what you're looking at is the sheetmetal (gasket) between the actual ports. This part of the gasket isn't sealing anything, just the area inside the 4 bolt pattern that is raised to the shape of the port is where the sealing is happening.
Do you have any leaks @ the ypipe /manifold mating surface? Is it a heavy or light metallic noise? Jack up the car and have a partner kick his foot on the brakes and give it gas in "D" and "R", while you look for the source....

 

it's a light metallic noise.. and i drive a stick, so i'd have to find a different way to do that experiment.. it's gonna get checked out tomorrow though, so we'll see whats up.. my friend said he thinks it's the y-pipe... but i know cattman makes quality products, and i doubt if that's the case

 

It's something small hitting it or maybe the engine mounts are worn...What kinda exhaust hangar supports are you using? You sure your exhaust hangar mount are up for the task? I bought Nismo and NAPA brand exhaust hangars, and the NAPA are just as good as the more expensive NISMO's.

 

well as far as the engine mounts, they were fine before the header install as far as i know.. i dont know why they would all of a sudden get worn to the point where they started making noise.. the exhaust hangar supports are stock, and the noise is coming from towards the front of the car

 

might have a dust shield clearance issue with the larger piping.

 

check for clearance between y-pipe and front engine crossmember. On mine the clearance is very tight, on others it has more room.