CapYoda

well um I was bored so I got myself a header for my 7th gen civic ex... didn't expect any performance gains but like i said, just for fun.

anyhow, after the installation, I'm having some problems.

I think I have a leak somewhere... since I can smell the exhaust fumes easily when I open up my hood.... I feel like fainting right now in fact, smelled it more than necessary today. the car also makes a rattling noise... you know those noise a car with a broken exhaust system makes? yuck.

I didn't replace the stock gasket yet... only had the car for 15,600 miles, should I replace the stock gasket?

I overtighten one of the bolt that connects the header to the heaer, and now its sorta loose. you know how you can turn it and it gets tight and tighter and then suddenly it becomes loose? and the cycle repeats as you keep on turning the bolt? is that because the bolt is stripped?

and finally, there's an opening for a o2 sensor, and I plugged that up with a 3/8" bolt... I couldn't super tighten it because my socket wrench set is metric (mm) and I didn't have any that would fit the 3/8 easily... so I just used a monkey wrench that has little or no torque.

anyhow. anyone got some ideas whats wrong? I think the leaks could be any of the ones listed above, but I really can't figure out the rattling.

crucial Si

its not from that bolt that is loose..i have one that is total broken off and i dont smell anything like that...so. did you hook it up to the cat correctly?

CapYoda

well the 01+ civics have a different exhaust system... it consist of:
the header, a mid section pipe with an o2 sensor that leads to the cat.. and after the cat there's another o2 sensor.. then the rest of the cat back...

the header I got is an upper section only...

well maybe I didn't connect it too well to the pipe that leads to the cat... I guess thats something I can check out tomorrow.

oh yeah thanks for the idea.

Bakeoff

that sounds like your problem.