I got the exhaust system made for my wagon and there is a noticable leak at the exhaust manifold to exhaust pipe union. I tried tightening it down to the point of bending the flange and it still leaks. I've never had an issue like this come up before but then again I havn't messed with too many V8's. Are there any oldtimer tricks out there I can try before taking it back and seeing what the deal is? I'm thinking I'll take the manifolds off and make sure they are smooth at the union and try putting it back on. Is there any sort of sealant or gasket that has proven itself in the past? Thanks all, NAES
i have banged in a short piece of pipe that fits tightly in the manifold and goes into the pipe far enough to bridge the joint.
if memory serves me right 2" should be gm part number 3731062.hope it helps you i think the 2 1/2 is a FPG 9587 napa part number
I have successfully used High Temp Copper Silicone on both manifold to exhaust pipe, headers to block, and headers to exhaust pipe seals.
Sweet. All good solutions. Ill dive under there and see what i can make work. Thanks all. As usual you all have the answers.
$ Remember forgiveness is always easier than permission $ X2 all I have used for 15 years now and never had a leak yet.
If it's a stock Chevy manifold and a flared pipe, you need a donut, and if you use a composite donut (not cast iron) then you also need a short piece of tube inside the donut to keep it from collapsing. A lot of folks don't know about the inner tube...they fight leaks for years
Exactly right My Son's '66 Nova with a small block w/rams horns needed that tube in the head pipe to seal properly!
I should have been more specific. Im running a chrysler 360 with stock manifolds. Ill look for a donut and if that doesnt work ill use the silicone.
If it's a flat flange, then you need to make sure the flange on the pipe is thick enough so it wont bend, and that it's perfectly flat. Use a steel core graphite type gasket, or perhaps one of the formed copper ones. If it's a ball and socket type joint with a flared tube, you need to get the flare shaped right, or it won't seal. btw it does help to give all the details the first time...
One word of caution... Chrysler exhaust manifolds are much more prone to warping than the other brands. Get a 3 foot piece of fuel or air hose, Put one end to your ear and move the other end all around the gasket surfaces at the head and the down pipe. You will be able to locate exactly where the leak is. You cannot tell exactly where the leak is by just looking down at it. If you find out that it is at the head surface send the manifolds out to a machine shop for surfacing. The shop that I used had a large table top belt sander that was used to flatten the gasket surface at a very reasonable price. Just replacing the gasket is only a temporary fix until the new one burns out too. Never a problem with GM and Ford manifolds but Chrysler's were a problem. BTW when I was asked how is the muffler business... I always answered exhausting!
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