I'm having a heck of a time trying to seal up my header to my Cylinder head. I have a Doug Thorley header and an EB Cylinder head. Any options to try and seal it up? I've tried replacing the gasket with a new one this weekend and it just got LOUD, only when I step on the gas. Sounds horrible! I can also feel the gas escaping from the gasket if I put my hand near the flange. Is there a sealant that I could use, or is there a better choice in gaskets somewhere other than EB's? I've tried using 2 gaskets (one eb's and the other came with the Header) togeather and that almost sealed it up, but not quite.

Thanks for any advice,
GOI <img src="/forums/images/graemlins/kewl.gif" alt="" />

I had a similar problem, but on a totally different vehicle, for what it is worth.

Thorley headers on a Chevy 350 small block. One sealed just fine, the other did not at all. The flange was warped on that side, I put a straight edge on it and you could see the curvature of the flange. The bolts would torque out on the wrench (click) before the gasket was properly preloaded, resulting in a blown gasket. You could not see a gap, but there was not enough pressure on the face of the gasket.

Thorley ended up replacing it, but it was a pain, had to send them the header at my cost to evaluate, then they reimbursed me.

I would get a good, known straight edge and check the head and the header to see if either is out of flat by a significant amount.

A cheap fix to try, get a new gasket if yours is too bad to reuse. Apply a bead of high-temp exhaust silicone around each exhaust port on the gasket, both sides. Let it 'skin up' them install header. The silicone will help to fill any low spots in the flange. This has worked for me in the past. Also install with new locking nuts for the manifold studs, if they don't lock they will loosen up and you will have another leak.

Well I went to the autopart store to see how much it would cost to get a new gasket. They Wanted $30.00 <img src="/forums/images/graemlins/zombie.gif" alt="" /> So I made them show me a picture of the gasket and it looked to be the same thing that I got from EB in my Head Gasket kit. But it also showed 2 other small gaskets that came with it. So I went home and found those other gaskets pictured and put them on last night. I'm guessing that these went on the upper 2 bolt studs at each end, it's where the exhaust was leaking from. I also Siliconed everything! Hopefully it seals this time.

To conclude, it was my own fault to not have noticed those 2 smaller gaskets that apparently go on too. Does anyone know if I put them in the right spot? <img src="/forums/images/graemlins/scared.gif" alt="" />

Thanx,
GOI <img src="/forums/images/graemlins/kewl.gif" alt="" />

Two small gaskets go under the EGR block-off plates or the exhaust injection tube flanges: