First time thermostat change, need advise.

Discussion in 'Fox 5.0 Mustang Tech' started by Rerun, May 15, 2004.


  1. Rerun

    Rerun Founding Member

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    Going to change the thermostat tommorrow, I don't think it's working properly. Ended up getting a Stant Super-Stat from local auto parts store and also picked up a waterneck gasket.

    My question is, how should I go about this. Do I have to drain the radiator? From what I can tell I just take off the upper radiator hose from the water neck, unscrew the water neck. Clean off the waterneck, take out the thermostat and replace it with a new one. Put a fresh gasket on the waterneck tighten it down and reattach the upper radiator hose. That sound about right or am I missing something? Also, this thermostat doesn't appear to have a hole in it, i keep reading about this.

    Anyone want to elaborate on the installing of the thermostat issue so I don't **** something up.

    Appreciate it fellas.
    #1
  2. TC93

    TC93 Well-Known Member

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    It sounds & looks simple, but that can be the most frustating task to do.. :mad: The bottom bolt can be tough to get to and the little hose to the water pump can cause you fits, along with the T-stat falling out of place when trying to install everything. But be patatient and you will get it. The major thing is the T-stat slipping out of place when installing the water neck. You will know it happened when you refil it with H20, it will leak on the bottom of the water neck.You don't have to drain all the antifreeze/water, I usaaly drain about 1/4 or 1/2.
    #2
  3. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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    Dumb question...is the thermostat gasket the same as the waterneck gasket....if not where can I get a waterneck gasket?

    Thanks...
    #3
  4. TC93

    TC93 Well-Known Member

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    The thermostat itself doesn't have a gasket. The gasket goes between the lower intake and the waterneck housing. And the t-stat sit's inside/between the two.
    #4
  5. 87'GTstang

    87'GTstang New Member

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    Hell yeah :bs:

    The technical name for it is the thermostat housing and the gasket you are referring to is basically the same thing.
    #5
  6. battyice

    battyice New Member

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    t-stat

    Tip: When you get the thermostat housing removed and cleaned, put it in a vice or some sort of clamp and put a light layer of high-tack gasket sealant on the gasket surface. Then you can stick you gasket on and if you're careful, it will hold the thermostat in place and allow you to easily bolt everything back up.

    Tip #2: A short box-end wrench can be very helpful for loosening/tightening the thermostat housing bolts.
    #6
  7. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    since it is your first time, make sure you dont put the stat in backwards. it has been done. also, though you have one, they sell adhesive backed gaskets, which accomplish the same idea as what Battyice suggests.

    also, i agree with Battyice on the box end wrench. i have had the best luck with one of the ones that ratchets....next time, im gonna go get an allen bolt that is the same size, so that i can use an allen wrench, which will hopefully allow much faster and more productive turns. 1/64 of a turn gets old. LOL.

    and if your stat came with a bleed hole, make sure you orient it properly. a little silicone spray on the male fittings on the bypass hose helps to slide the hose on. if you have doubts about it, replace it (costs under 5 bucks).

    good luck.
    #7
  8. 5spd GT

    5spd GT "the 5.0 owns all" Founding Member

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  9. Michael Yount

    Michael Yount Advanced Member

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    Drain coolant below the level of the lower intake - you won't have to drain it all out. Remove the upper radiator hose as well as the small bypass hose that runs from the water pump to the t'stat housing. It would be a good time to replace both those hoses unless they're relatively new -- especially the bypass hose. Remove the two bolts and remove the housing/t'stat. Get the new gasket that has adhesive on one side - very important step!!!! Clean the housing and manifold surface of all remaining gasket material. Insert the t'stat into the housing so the spring faces into the manifold. Clean the whole area (top of the front cover) and be sure there is no coolant anywhere - you want to be able to distinguish a new leak from coolant that spilled as part of the job. Peel off the adhesive backing and use the gasket to "stick" the t'stat in the housing. As mentioned above this will hold the t'stat in place and keep it from sliding down and causing a leak. Put just a bit of gasket dressing (hylomar blue - NOT RTV - no need for any silicone at all) on the non-adhesive side of the gasket, put the housing in place and replace the two bolts. Note that one is longer than the other -- you may want to use a bit of thread sealer or never-seize on the threads. Once it's snug, re-install your bypass hose, and then your upper hose (in that order) - hopefully new hoses with new clamps. Refill, check for leaks, run/burp air out of the system, and then drive (close to home) to be sure all is working.

    The biggest errors made by people are 1) not using the adhesive backed gasket which is designed to hold the t'stat in the housing until you get it installed, and 2) not removing the upper and bypass hoses completely. It's extrememly difficult to get the alignment you need if you leave the bypass hose attached to the intake manifold.
    #9
  10. Rerun

    Rerun Founding Member

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    Awesome thanks bud, I ordered a Mr. Gasket 180 and I'm going to pickup the adhesive gasket you guys spoke of. Once I get it, I'm going to take a stab at this. Thanks a million.

    J.
    #10
  11. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    very nice choice on the stat! i had a parts store variety 180 and ditched it in the same week for a MR G 180. you will laugh when you compare the two side by side (think Yugo vs a Benz). the Mr G is much more efficient (opens fully sooner, flows better, and has the bleed hole).
    you wont be disappointed, IMHO. ive been preaching those units for some time.
    #11
  12. Rerun

    Rerun Founding Member

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    So I was looking on JEGS is the Mr. Gasket thermostat gasket adhesive it doesn't say? If not do you guys have any recommendations?

    I know i'm a pain in the ass, but i'm new and I'd really hate to **** something up so I guess better safe than sorry.
    #12
  13. Michael Yount

    Michael Yount Advanced Member

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    Just run to your local parts store and ask for the adhesive-backed gasket. I've bought them at AutoZone, O'Reilly's, etc.
    #13
  14. TheUser

    TheUser Active Member

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    I asked for the adhesive backed gasket at Autozone and he told me they don't make such a thing. Ended up having to pull it again later for something else and went to O'Reillys this time...they had the adhesive backed gasket, so not everyone carries them, at least not here.
    #14
  15. The Shape

    The Shape Founding Member

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    It always seems to help me if I cuss alot while trying to get the bolt on the right side out LOL.
    #15
  16. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    when i did my stat (the previous owner had had the stat replaced with a parts store 195), i found the adhesive-backed gasket with the backing still on it. LOL. kinda defeated the purpose - like using double sided tape and not taking the wax paper off.

    if you have a local speed shop, they should have the Mr G stat. mine was 10 bucks from Don's (local hot rod shop).

    and dont sweat the questions. i cant recall the number of times i have muttled through something, only to later read a post from Michael and/or others, outlining a better way to do it. i think, "DOH, you should have asked."

    good luck.
    #16
  17. Michael Yount

    Michael Yount Advanced Member

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    Yes, cussing helps alot with those bolts, and with getting that @#%@^^ing bypass hose back on. I feel better already.....
    #17
  18. TheUser

    TheUser Active Member

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    Cussing :nice: By the way, i'm not sure if it's the correct way to do it or even the smartest, but I put the little bypass hose on the water pump first and then used a flat screwdriver to push the bottom part onto the bottom of the thermostat housing connection and the rest fits right on...worked for me. I suck at coolant systems though, I have a hard time doing it w/o leaks :bang:
    #18

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