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help! i just changed the thermostat

Discussion in 'Truck & Equipment Repair' started by djlouieboom, Nov 6, 2005.

  1. djlouieboom

    djlouieboom Junior Member
    Messages: 19

    on my 95 gmc truck and i put form a gasket on before reassembly and the dam thing leaks! any sugestions ?
  2. DugHD

    DugHD Senior Member
    from Maine
    Messages: 420

    did you actually use form a gasket ? Or did you use a gasket sealer? Sounds like you need to do it over with gasket or better sealer. Good luck
  3. djlouieboom

    djlouieboom Junior Member
    Messages: 19

    i put the gasket in that came with the thermostat and then put forma gasket on the housing and the base any sugestions on a good gasket sealer ?
  4. SnowGuy73

    SnowGuy73 PlowSite Fanatic
    Messages: 24,870

    Is the houseing cracked, did you tighten it enough, is there too much sealer on there....These are all things to look at.
  5. DugHD

    DugHD Senior Member
    from Maine
    Messages: 420

    If you used the gasket that came with it you didnt need forma gasket , Just some gasket sealer . Permatex makes some good products. Good luck
  6. djlouieboom

    djlouieboom Junior Member
    Messages: 19

    ill check it all over tomorrow and let you guys know how i make out thanks
  7. justme-

    justme- 2000 Club Member
    Messages: 2,138

    Which form a gasket did you use? Was it real form a gasket or silicone?

    Did you clean the thermostat houseing and block's gasket surfaces before reassembly? Was the gasket a good gasket (not folded or torn/tattered from the box)? Did you use the form a gasket properily?

    Real form-a-gasket is available in a couple numbers, #2 is the non hardening, which is what I recomend.
    Rubber gaskets don;t usually need anything but a little grease, paper or cork get #2 on one side only, this is just to allows the gasket to stick in place and make my life easier in assembly, then a little common grease to the other side which lets the gasket slide a little if it needs to when compressing during tightening or aligning for putting thr bolts through.

    This is for all gaskets I install- and make sure the surfaces are clean and undamaged.

    Silicone needs to set first (as does #2 permatex) before assembly. if not it will not seal properily the majority of the time causeing leaks.
  8. SnoFarmer

    SnoFarmer PlowSite Fanatic
    from N,E. MN
    Messages: 9,883

    Never goop a gasket.. use one or the other,(goop or gasket) you can not get away using a gasket maker in every situation, your better off using a new gasket. Drop the thermostat in first then the gasket make sher the thermostat is in place and reassemble, on some, if the bolts go into the water jacket you will need to use thread sealer, not silicone or thread locker.
  9. djlouieboom

    djlouieboom Junior Member
    Messages: 19

    i used permatex ultra black high temp rtv on the housing and put a new gasket in everything is great no leaks :) thank god,... now ill i need is some snow to push hahaha:p