best sealant option for freeze plugs?

Discussion in 'Engine/Drivetrain/Suspension' started by JasonB, Feb 23, 2006.

  1. JasonB

    JasonB Administrator Staff Member

    anyone recommend a sealant for freeze plugs? I'd hate to end up replacing them after the motor is in.

    what about a good thread sealant for the oil galley plugs?
  2. outalne94z71

    outalne94z71 Well-Known Member

    freeze plugs are self sealing brass, if you put sealant on them they may not pop out when they are supposed to, but then what are the chances that it would ever get cold enough by you for that

  3. JasonB

    JasonB Administrator Staff Member

    well i read in several places to use sealant on them, but i do not recall ever doing that before (nearly 20 years ago the last time i rebuilt a motor)
  4. outalne94z71

    outalne94z71 Well-Known Member

    i did a little searching, and your right alot of places are recommending to put a little sealant on the contact surface

    ive rebuilt many motors over the years and never heard of anyone doing that till now
  5. Mr Joe

    Mr Joe New Member

    I also don't recall using sealant. :sorry:

  6. JasonB

    JasonB Administrator Staff Member

    hence my confusion. perhaps they are referring to steel plugs and not brass?
  7. trail_lover

    trail_lover New Member

    A little RTV . a little on your finger wipe around the sealing serface , install core plugs (frost plugs)

    for fittings i always use teflon tape . rape the threads in the drection of the threads so that when you thread the fitting the tape does not come off .
  8. WMIF

    WMIF New Member

    i always get the block back with the plugs installed by the machine shop.
  9. trail_lover

    trail_lover New Member

    use a seal installing tool , make sure you are square to the block . dont just use a hammer you will bend the mating serface and it will leak .
  10. 74 chev

    74 chev New Member

    i use brass ones and have never had a leak :dunno:
  11. KB440

    KB440 New Member

    With brass plugs I never use anything, but with steel plugs I use RTV.
  12. Tango

    Tango Well-Known Member

    use RTV and let it setup for 48 hours.

    on a street truck you don't really need if BUT offroad if you don't put it they can vibrate out.
  13. RamSport59

    RamSport59 Well-Known Member

    Boss...on my jasper engine when one of the freeze plugs popped on me, Jasper told me to use a certain # of Locktite. I can remember the number. but It had to set for 8 hrs then i pressure tested....It lasted at least 25k miles then and someone else is now driving it.

    I'd check into that if I were you!!! I definitly recommend using sealant...

  14. steved

    steved New Member

    I always use Permatex Gasket Maker...the black sticky stuff in a tube (looks like tar), not RTV. Coat the entire inner face of the plug with it. Most plugs I have taken out were rotten in the center for some reason...maybe the block acts as an anode??

    If you use brass, I doubt sealant is needed. Steel, I think the idea is to prevent them from rusting out.

    And how does a freeze plug vibrate out?!?!? :loser:

    My only advise is don't punch them in too far.

    And if you are worried about them "vibrating out", you can drill and tap the block for small screws and add a piece of strap steel across them to prevent them blowing out under high RPMs. Brass plugs are nice because they are corrosion resistant, but they are also softer, don't hold in the block as well, and can pop out...although I have only seen this once at a drag strip.

  15. JustRamIt

    JustRamIt New Member


    Freeze plugs arent supposed to pop out when it gets too cold so your block wont crack. Freeze plugs are there for inital casting purposes only from the factory.
  16. ZacD

    ZacD New Member



    The only time I've ever seen a pressed-in freeze plug (brass or steel) "pop" out due to engine load/vibration was at a drag race. 550+ horsepower and 7000+ rpm in a late model, thin casting 5.0/302 Ford block is living on the ragged edge. This guy puked a freeze plug out of the block (probably due to the block twisting) out at about the 1/8th mile, in the finals.

    I have always run brass plugs and never used any sealant. The way I look at it, more likely than not, if I ever have to worry about a brass plug failing, the motor's probably given up the ghost long before that, or I've got some big time problems above and beyond a freeze plug.