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Advice please, on thread sealant

Discussion in 'The Hokey Ass Message Board' started by Big Bad Dad, Jan 10, 2010.

  1. Big Bad Dad
    Joined: Mar 27, 2009
    Posts: 317

    Big Bad Dad
    Member

    I am replacing the headers on my O/T Dodge pickup with a 360. One of the exh manifold studs broke off flush with the head. It is one of those that goes into the water jacket. After much work, I was able to drill it out and re tap the hole. The new stud screws in nicely, but I am afraid it is just a little on the "loose" side. I am pretty sure a heli coil would never seal here. My thoughts are to take a q tip and fill the hole with #3D Permatex Aviation Form a Gasket sealer, dip the stud in the same stuff, tighten it securely, and let it set up for a week or two before adding coolant and firing the engine. Any body ever done this and think it will work OK? Or have a recommendation for a different product to use? Maybe old style gasket shellac? Thanks for any useful advice. :)
     
  2. Adam Bahm
    Joined: Nov 12, 2008
    Posts: 27

    Adam Bahm
    Member

    I butter up both threads with JB weld. Make sure stud is perpendicular to mating surface if it is a loose fit.
     
  3. Big Bad Dad
    Joined: Mar 27, 2009
    Posts: 317

    Big Bad Dad
    Member

    Thanks for that advice, but I don't think I am at the point of needing the JB Weld. The threads are tight enough that I would be OK with them for a 5/16 USS bolt thread to hold the headers, I am just concerned about sealing the threads to prevent a coolant leak. I am wondering if the Permatex Aviation Sealant is OK or if anyone had experience with other sealants. I don't want to have to re do this once it goes together! :)
     
  4. RopeSeals???
    Joined: Jul 2, 2007
    Posts: 444

    RopeSeals???
    Member

    I used teflon tape after I had leaks when I removed the studs and went to bolts due to a clearance issue on a 318 header installation...
     
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  5. V8Mongrel
    Joined: Dec 4, 2008
    Posts: 35

    V8Mongrel
    Member
    from Apex, NC

    I have found Permatex High Temp Thread Sealant to be superior to Teflon tape in every respect other than affordability. I don't believe that the Aviation Sealant suggested is designed for use as a thread sealant. I thought that it was for machined surfaces mated without a gasket. I also don't know for sure if the High Temp Thread Sealant will withstand being on exhaust fasteners, but I have used it various engine fasteners and never had a single issue. The Permatex website has a lot of information.

    Don't cheap out and buy some no-name liquid Teflon from the hardware store either. A non-High Temp Sealant is available from Permatex and I am sure it is excellent, but my experience has been that the cost differential is minimal, and especially in this case, so why not get the higher heat range? Once you use this stuff, you'll forget Teflon tape ever existed.
     
  6. Big Bad Dad
    Joined: Mar 27, 2009
    Posts: 317

    Big Bad Dad
    Member

    OK, I did thanks for the info. The local Autozone has the Permatex hi temp thread sealer in stock. :)
     

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