Exhaust sealant question

leadpot

leadpot

Senior Member
Had to remove the intake/exhaust manifold to repair the distributor hold down bolt that was stripped out. I did not separate the manifolds & all the flanges are good/flat with a straight edge. Am ordering the one piece gasket like what it had on there. Around a couple of the exhaust ports there was evidence of black soot/leaks. When reassembling do you use any type of sealant on the gasket?

Would like some opinions on a separate issue. I found a small visible crack on the intake manifold going from the vacuum port to the top of the manifold. I was going to drill a hole at the end of the crack & then Dremel the crack & then repair with JB weld exhaust epoxy.
Thanks,
 
If you ordered the one-piece aluminum-clad manifold gasket, you will never be able to seal the exhaust leaks. That you found signs of black exhaust soot underscores the poor sealing capability of that particular gasket. I have never seen it seal worth a darn. You are better off ordering the copper-clad gaskets that DO seal. Yes, they are more expensive - quality always is. But why throw away less money for something that won't work? Spend the extra few dollars on copper-clad manifold gaskets and stop those pesky exhaust leaks.
Marshall
 
Marshall V. Daut said:
If you ordered the one-piece aluminum-clad manifold gasket, you will never be able to seal the exhaust leaks. That you found signs of black exhaust soot underscores the poor sealing capability of that particular gasket. I have never seen it seal worth a darn. You are better off ordering the copper-clad gaskets that DO seal. Yes, they are more expensive - quality always is. But why throw away less money for something that won't work? Spend the extra few dollars on copper-clad manifold gaskets and stop those pesky exhaust leaks.
Marshall
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As usual, Marshall is 100% on the money! Not a fan of the green paper ones that come with the gasket kits either.
 
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Yup to all follow-up posts.
I smear a very light coat of muffler sealant paste on the intake manifold's runner ports to get extra sealing against leaks here. Probably not necessary, but it does give me peace of mind. Vacuum leaks cause all kinds of idle problems, almost always originating from the intake manifold not sealing properly, sometimes emitting a tell-tale whistling sound, sometimes not.
I'm with Y-Blockhead, as usual. I routinely toss those toilet paper strength green cardboard gaskets as soon as I open up the engine gasket kit box. I wish the maker would offer the option of substituting those worthless Confederate money shingles for copper-clad gaskets with a reasonable increase in price. Otherwise, I have paid for those green gaskets many times over the years, only to immediately throw them away. That adds up to a lot of money paid for nothing. :(
Marshall
 
Y-Blockhead said:
As usual, Marshall is 100% on the money! Not a fan of the green paper ones that come with the gasket kits either.
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I had a pair of those lying around closer than hiking out to the shed for some copper ones. BIG MISTAKE they lasted about 3 miles. It was on a header and the flange wasn't exactly flat but it hadn't been leaking with the old copper ones.
PS - An hour later with the press and a torch the flange is now nice and flat.
 
I have actually had good luck with the long 1 pc gasket I changed mine about 3 years ago and to this day I have no leaks I do keep an eye on the torque!!!
 
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