ticking noise on accel 96 4.0

I just replaced my exhaust manifold with a dorman,and when i accel. in the morning when its cold i hear a ticking noise. when the jeep warms up the noise gets quieter but can still here it if you listen for it. i thought it was either the manifold gasket or the donut seal. i double checked to see if all the bolts were still tight. and they were. still making the noise. so i took everyting apart again and put a new mopar gasket and new donut seal and used peratex copper gasket sealer on it. drove it again and can still here the noise.
when the jeep is idieling you cant here any noise even when you rev the motor. its only when you drive it. what could the noise be.

thanks, by the way is a 96 4.0

If there was no tick before you replaced the exhaust manifold and there is a tick now then there must be an exhaust leak somewhere.

it could be ur hearing the valves ticking more because of the thinner wall headers

I'm having this same problem too. More than likely, like mine, you have a leak. Mines in the #5 Intake port, so mines down till I fix. Seems like the Dorman headers are causing a lot of grief.

it is likely it is the exhaust leak, but there is a chance it could be due to carbon buildup. You might want to try to run a can of Seafoam through it...either way it can't hurt.

OK, I've had some time to delve into the Dorman manifold issue a bit, now that I've blown my second manifold gasket.

After removing the header and taking to my NAPA dealer, we threw a straight edge across the manifold and discovered it warped by about 1/16 inch, with the high spot in the middle. Even worse, the "ears" on the end pipes were warped inward such that when torque was applied to the outside bolts, the inner bolts on #1 and #6 flanges wewre lifting and preventing contact with the gasket. It was much the same problem as shown in the photos here: http://www.naxja.org/forum/showthread.php?t=98813 (post #8). In my case, the gasket was creeping from the exhaust back pressure and tearing at the intake manifold. My 1st gasket lasted about 200 miles until I put on a legal exhaust (work in progress). Then, I'd get one or two warm ups and blow a gasket.

The NAPA dealer ws great and took it back no questions asked (Kudos to Reibe's in Grass Valley). One advantage of customer loyalty. Here's where it gets intersting: We looked at two more manifolds with a straight edge right from the box and both of them were warped out of spec as well (spec is .017") in completely different ways. They ordered two more in from their other stores and we'll pick the best of 5.

Looks to me like Dorman has some QC issues, so if you have a recently-purchased Dorman header, and are experiencing vacuum leak symtoms, you may want to check your manifold for warping, particularly if you see the tell-tale offset intake/maniflod flanges.