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Can't get rid of this exhaust leak!!

Discussion in 'The Hokey Ass Message Board' started by Gasoline Junkie, Feb 19, 2012.

  1. Gasoline Junkie
    Joined: Nov 20, 2010
    Posts: 328

    Gasoline Junkie

    I have an exhaust leak at the manifolds and I just can't get rid of it. I tried 4 different gaskets and no luck. I even tried doubling up and it was the best i've gotten it so far. In my last attempt, I made sure to scrape off all the old gasket(s) and use a fresh set of lock washers. Now it leaks even worse. I think maybe my manifolds aren't straight? Or should I try tripling up on gaskets? I've been told that you can get away with no gaskets with manifolds. What can I do?
  2. Can you pinpoint the location?
  3. FIFTY2
    Joined: Apr 9, 2008
    Posts: 334


    Manifolds may be warped, you can check them with a straight edge next time u have them off...

    What engine/manifolds are you running?
  4. DavidL
    Joined: Oct 6, 2006
    Posts: 82


    What type of motor and manifolds do you have? (fifty2 beat me to the question)

  5. Live with it?

    Sorry I haven't been an ass yet today and you were available. ;)

    I am not sure what you are working with, but you can lat a straight edge across the manifolds and see if they are straight, if not you can have them faced.

    Or something that I have done with good sucess is use Permatex Silicone with copper in it. It holds up to the heat real well. This obvoiusly not the high tech way to cure the problem but it wirks. I still use gaskets when I do this and I give it some time to cure before lighting it off.
  6. Gasoline Junkie
    Joined: Nov 20, 2010
    Posts: 328

    Gasoline Junkie

    I can't pinpoint it, it only really does it under load. I'm running a 350 with ceramic-coated manifolds
  7. slddnmatt
    Joined: Mar 30, 2006
    Posts: 3,679


    I had a one the other day I couldn't find at the header. ended up being a hairline crack on the flange . Now its nice and quiet!
  8. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    Member Emeritus

    Take a 3 foot piece of air hose or 3/8" fuel hose, hold one end to your ear with the engine running and run the other end around any joint, gasket or bolt. You will find it when you get close and then you can figure out why it is leaking and correct the problem. Don't forget to come up from underneath.
  9. Ceramic coated manifolds, as in ceramic coated headers made from tubing or manifolds as in cast iron factory pieces that you have ceramic coated.
  10. Stroker McGurk
    Joined: Feb 17, 2012
    Posts: 291

    Stroker McGurk
    from Canada

    Take the manifold off and get it surfaced......
  11. Gasoline Junkie
    Joined: Nov 20, 2010
    Posts: 328

    Gasoline Junkie

    They're cast manifolds, not tube headers. I'll try the "stethoscope" trick but maybe this is an excuse to buy the headers I've had my eye on!
  12. jesse1980
    Joined: Aug 25, 2010
    Posts: 1,355


    if it isnt to much and too hard to find i would replace the manifolds. sounds like they are the problem.
  13. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,956


    Napa sells a product make by walker part# 35959 exhaust cement put it on both sides of the gasket like sealer. I used it on a manifold and head that had leaked so long it had eroded. It's been years and it's still OK.
  14. flat 39
    Joined: Dec 31, 2007
    Posts: 229

    flat 39

    Thanks for the info. I have a ford FE with a manifold leak.
  15. 32v
    Joined: May 20, 2007
    Posts: 949

    from v.i.

    had the same problem turned out to be a crack flex plate
  16. mastergun1980
    Joined: Oct 18, 2010
    Posts: 1,095

    from Alva OK

    I have fixed trickt exhaust leaks with copper gaskets in the past. Headders and manifolds. They arn't cheap but neither is 4 sets of regular gaskets.
  17. I use remflex on my FE's and they handsdown work! Even had a set warrentied without anyproblems.

    Check the manifolds for straightness, smooth them out if need be and try out some remflexes.

    Also If you cant pinpoint the leak, seafoam ur engine. When you start it up it will puff white smoke from the leak.
  18. squirrel
    Joined: Sep 23, 2004
    Posts: 46,716


    Chevy did not use gaskets on the manifolds on 350s.
  19. Ha, Ha. :D:D:D

    I had a ticking lifter that I chased for a month and it turned out to be a leaking header flange/gasket. ;)
  20. squirrel
    Joined: Sep 23, 2004
    Posts: 46,716


    yeah, I was gonna suggest checking the valves!
  21. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 7,495


    Turn the radio up a little louder,that works for all the little noises I dont want to hear.
  22. Standard gas&oil
    Joined: Dec 3, 2010
    Posts: 289

    Standard gas&oil
    from USA #1

    I have had real good luck with regular gaskets and high heat copper permatex. Never a leak.
  23. Tony
    Joined: Dec 3, 2002
    Posts: 7,350


    And, i've run MANY with nothing more than high temp black permatex as "gaskets".
    Apply a normal amount to the manifolds then bolt em on. start it to let it heat up then shut off to cool. Snug up the bolts for good measure and you're done..
    That is providing the manifolds are not warped. If yours are, have them surfaced as was mentioned and give this a try. You may be surprised.
    I even did the manifolds on my 62 Impala 409 that way..NO leaks.

  24. squirrel
    Joined: Sep 23, 2004
    Posts: 46,716


    I never use gaskets or sealer on Chevy V8s with manifolds, and they don't leak. but I use old used parts, not fancy plated stuff.
  25. MrMack
    Joined: Jan 24, 2012
    Posts: 5

    from Oregon

    I have used Remflex gaskets where other gaskets would not seal and have been pleased with them.
  26. What he said.........
  27. Gasoline Junkie
    Joined: Nov 20, 2010
    Posts: 328

    Gasoline Junkie

    No radio :D

    Already checked the valves haha

    I definitely think the manifolds are warped, because after this many sets of gaskets there's obviously a problem somewhere, right? So if they are, how much and where can I get them resurfaced? I mean, I could find a decent pair of tubes cheap from Summit anyway
  28. Mr.Bomba
    Joined: Apr 13, 2007
    Posts: 358


    By the time you get the manifolds surfaced your most likely gonna be half way dollar wise into some headers... so if youve been eye ballin em you might as well buy em and call it a day!! just my 2 cents...
  29. Licensed to kill
    Joined: Oct 4, 2009
    Posts: 214

    Licensed to kill
    from Alberta

    Years ago I had a truck with a 454 that had warped manifolds. They were REALLY warped and there was just no way to seal them up. A guy suggested "Ultra copper" silicone. I told him "you don't understand, the manifolds are warped, it's leaking where the manifold bolts to the head". He said "yup, I know, use the silicone". I thought he was retarded to even THINK that silicone would stand the heat ESPECIALLY since the truck was running on propane which creates higher exhaust temps than gas. Out of desperation, I tried the silicone and, wouldn't ya know, IT WORKED and these manifolds weren't just warped a little, they were warped alot.
  30. Tacho
    Joined: Aug 21, 2009
    Posts: 85


    I had a bad leak and went through 2 sets of gaskets...different brands too. Took them out and spanked the ram horns right on the port and no leaks. Horns are silver and don't see any marks from the exhaust.

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