rattling noise after header install

[adham]

after installing my headers and catted y-pipe i have been experiencing alot of rattling/clicking noise
i went to the muffler shop and got the y-pipe welded to the catback because it was leaking
now that is taken care of but i cant figure where the rattling is coming from
the guy at the muffler shop said it was the cats
he said they were broken from the inside or something
they are brand new from MAC and came with the headers
is this guy talking out his ass?
i checked all the bolts and they are tight
i dunno what is causing it
has anyone experienced this before?
PS: the cross-member that held the stock system together is not on because it will not fit

[mrr23]

you'll have to look around under the car and see what's hitting where. header, y-pipe, etc... hitting frame, body, etc...have the exhaust shop put it on the lift and let you hear the cats for yourself. if they are, make sure it's not the heat shield on the cats rattling. if it is indeed the internals of the cats, call MAC.

[easyericvan]

If its on the driver's side your y-pipe is probably hitting the heat shield. Mine was doing the same thing. I had a shop remove the heat shield where my y-pipe was hitting. If that doesn't work the bump stop hanger might fix it.

[keliente]

It may be a plain old exhaust leak...it sounds like a tick/click kind of noise that obviously increases with RPM. They may be leaking at the engine itself (perhaps a bad gasket or a bolt is backing out) or where the headers meet the y pipe...

[adham]

i had the heat shield removed during the install
no its not a ticking noise, did not mean to say ticking earlier
it does not increase with rpm
it is constant
how will the hanger help me in this case?
the system seems to be very sturdy/solid

[easyericvan]

It has a clamp that goes around the y-pipe. That hooks up to a support rod with 2 rubber bump stops in between that act kind of like shocks.