Ok, I just got a new DC Sports Header installed on my ls. Now there is a slight rattle coming from the catalytic converter and the car also sounds like there is an exhaust leak. Is the car suppose to sound like that with a header? The nuts on the supporting bracket for the secondary pipe broke off, so I just redrilled another hole on it. So now it has only 1 bolt holding it instead of 2. Could that be what's causing the rattle from the catalytic converer? Any opinons will be greatly appreciated. Thanks.

 

the support bracket could have broken in half and is now rattling. if this is the stock converter, the heatshields now may be loose.

 

Did you use a donut gasket? Did you reuse the springs? Doublecheck that all bolts are tight?

 

Using a new donut gasket would be a good idea, and the spring bolts are supposed to be torqued down to 16 lbs/ft

 

What's the donut gasket that you guys are refering to? Is there suppose to be a gasket between the header and the cat?

 

yes..

 

OK, it seems like that I was missing the donut gasket. Thanks guys. After putting that on, the exhaust leak is no longer there and the majority of the rattle is gone; however, there still seems to be a slight rattle when I am accelerating at around 1500rpm coming from the cat. I wonder if it's because I only have 1 bolt between the 2nd header pipe and the supporting bracket.

 

the heatshields is loose.

Same thing happend with mine, after the install of a DC 4-1 header, tha rattle appeared, took heat shield off, rattle gone.