Passenger side Header wont seal! What can i do?

I hate shorty headers exactly for this reason. I gave up and got longtubes. Now the flange is down where you can see it and work on it.

You'll need to unbolt the shorty and bend the flange back to it's original shape. Lube the stud threads or you'll have a stud come out and be having even more fun than you are now.

When trying to seal my gt-40p's headers, the passenger side had this wierd bend in the mating surface but I chose to ignore it. Well, I tried quicksteel, RTV, everything to get it to seal. Nothing will hold back pressurized hot exhuast gas. I bent it back to it's original shape but not before it mangled the recieving end on the h-pipe.

2 of the last 3 h-pipes I installed didnt have enough freedom of motion to be able to be manuvered into place for a seal. So I hacked off the mounting hooks for the hpipe and then I could bolt it up. Then I used a ratcheting tiedown to lash the exhaust into place.

how thick ar your flanges? i have 3/8 inch thick flanges and i would have to really wrench on them to bend em...

what kind of h-pipe you running? sometimes different brands just dont line up properly. take it to a muffler shop and see what they can do for ya....

trevor

I installed Mac shorty headers to a Mac H-pipe and had a similar problem. try l loosening the header keep the bolts in though then try to work it into place,you might need to hack off the H-pipe support for that side I then tightened the header to the H first then finished off the header to head bolts. It worked for me and the H-pipe hasn't moved in 3 years.

I've used Red High-Temp RTV in the past to seal up exhaust leaks where the header meets the h-pipe and it worked great for me. Just put a thick bead on, let it dry almost all the way and crank 'em down tight. I am anal when it comes to exhaust leaks and hear every little thing, this fix has kept me happy. As a matter of fact, I just put new headers and x-pipe on and they aren't sealed right, so I will have to do the same myself.

Loosen both bolts back up and retighten. Retighten them as evenly as possible -- down to 1/2 turn here, 1/2 turn there, etc. until they tighten up too much to do that. Then wrench on them and get them nice and snug. Should solve your problems.

Very few headers - even brand new ones - are completely true/flat across the flange sealing surface. And they should be. When they're not the problems include leaks, stripped threads from overtightening and bolts that back out/won't stay tight.

If you want to solve the problem - pull the headers off. Take a straight edge and lay it up against the flange surface. Chances are you're gonna see that it's not true.

The solution is to take them to a machine shop and have them true the flange. If it's a small gap, they can simply mill the flange a bit. That's what I've had done before. If it's really out of whack, they may heat the header and use a press to get it closer to true before they mill it.

It's the best way to solve the problem. To all reading the thread, the best way to go is to always check the flange for true before installing the headers. Once trued up by a machine shop, the header bolts right on and seals the first time. Chances are much better your header bolts will stay tight too.

I've seen Mac, BBK and FlowTech headers all brand new with flanges that weren't even close to true. My FRPP shorties' flanges were perfectly flat when new.

89MustangGX said:

Loosen both bolts back up and retighten. Retighten them as evenly as possible -- down to 1/2 turn here, 1/2 turn there, etc. until they tighten up too much to do that. Then wrench on them and get them nice and snug. Should solve your problems.

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This is what I do, and sometimes you have to tighten one side more than the other to get the ball and receiver to align where the system is sealed.