Exhaust leak secrets

Dave O

Dave O

Member
What's the trick to stopping a small leak between the exhaust manifold and muffler? I bought a new clamp, seal, and exhaust sleeve. made sure there was a good fit between the muffler and manifold mating surfaces. Still a small leak. Suggestions?
 
I paint the sleeve and seal and pipe flange and manifold flange with that muffler sealant paste. my manifold had some pitting.
 
I press the muffler/tailpipe tightly against the manifold when installing using a floor jack under the muffler. Of course I also make sure everything is lined up and use a muffler sealant paste.

Charlie Stephens
 
If you've got a correct fitting muffler (e.g., Aries) and a non-warped manifold, forget the gasket and sleeve, and just use muffler paste.
 
I do the same as Charlie and use a floor jack. Get it lined up perfectly and then drop the muffler away from the manifold just enough to apply a thin bead of muffler paste. Then lift it back into place and tighten the clamp. Works best with two people.
 
Examine the muffler pipe flange to ensure that there isn't an inward bulge or dent, or misshapen. The cheapie mufflers (Midas) that we were obliged to buy before the far superior Aires muffler came out in the 1990's had narrower flanges than was needed to effectively seal the pipe to the exhaust manifold. Coupled with inferior off-shore muffler clamps, it's a wonder anyone could even get a marginal seal back then, let alone not die of carbon monoxide poisoning. (I almost did in 1974 on a cross-country drive because of a poor-fitting muffler pipe!) If you have one of those older repo mufflers from the 1960's-1990's, it will be difficult to achieve a good fit and seal. You certainly don't need to add a bent or dented muffler flange to the equation.
It might be worth your while to remove the exhaust manifold and muffler. Test fit them on the garage floor to check for similar angles where they meet, no gaps or bulges. You may need to take a hammer and tap here and there to form-fit the muffler pipe flange to the exhaust manifold's flange. When bolting the pipe to the manifold, follow others' recommendation to use muffler pipe goop. I like the stuff from Snyder's. It's thick, goopy and stays put. Run a thick bead around the circumference of the muffler pipe flange and mate it to the exhaust manifold, ensuring that the pipe fits evenly all the way around and is not angled. A floor jack definitely helps so that only one person is needed.
Marshall
 
Dave O said:
Thanks for all the suggestions. If none of these work, out comes the welder. LOL
Click to expand...

Do you have a good, accurate repro muffler? The cheapies that were all that was available for many decades were terrible, if not hopeless.
 
I only use muffler paste and make sure you have it lined up good, push the pipe up in place with a floor jack. when tighten the clamp tap the clamp with a small hammer,
note make sure you put enough muffler paste on the pipe, a little film of it .is not enough. a good 1/4" bead work for me.
 
Exhaust sealant is GOOD stuff. I even use a skinny bead around the ports, on each side of the copper manifold gasket. It WON'T squirt out & look messy. Be SURE to re-tighten the manifold bolts several times, also do that to the exhaust clamp. Tap on the clamp & tighten again. Be SURE you have the clamp "RIGHT"SIDE UP & grease the insides & around the flange & manifold. After several tightenings, I did a pointy center punch "DING" on the stud threads, where they touch the top of the nuts. That's MY version of a SELF LOCKING NUT!---LOL---AND, use ONLY the COPPER laminated gasket, it's the BEST! I had a set that looked like they were made with BRAND-X gasket paper, WHAT A JOKE! They would BURN out, in a MINUTE & SEVENTEEN SECONDS!!!
OH, & be sure to use sealant inside the flange, OFTEN, the manifold surface is PITTED. Once on here, a Guy made up a cutter, to re-surface that area!!! Wish I were that BRILLIANT.
Minerva was testy about leaks, until I did these things.
Bill Practical
 
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Have no leaks since I installed an Aries muffler and Snyders exhaust/intake setup. Well worth the money
 
No leaks with my Aries muffler and ottwell manifold ! My trick is to make the manifold exhaust connection First, then the rear clamp to frame connection.
 
Hi Dave,

1. Per original question, "Still a small leak. Suggestions?" and,

2. Question,#15; and,

3. For other muffler interesting information; please go to:

www.amuffler.com

which recommends in writing and with drawn details much of what is suggested above, plus suggestions for other muffler and manifold related problems.
 
Try the non stock asbestos type exhaust gasket sold by suppliers. We have had very good luck, no leaking. Easy to install, one man job.
 
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