Thermostat housing


Registered User
This doesn't look right but is there suppose to be a dip in the bottom of the thermostat housing? Almost looks gouged or something. Redid my water pump and tstat, and no matter what I've tried it leaks from the bottom bad. I suspect this is the cause? Firs time doing this on the car since I bought it

I have a spare one luckily


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Registered User
I might of solved it. I didn't know there was a thermostat gasket itself with the water outlet gasket. Well that could be the problem. Oops


Registered User
I've seen that dip on all of mine, yes. Assumed purpose is related to locking/indexing stats (process outlined in the factory manual...insert and twist clockwise to lock). I can new find stats w/bleed holes but haven't seen locking stats in the aftermarket, so...

These housings leak easily, usually due to a warped base. I clean them thoroughly, then patiently wet sand the flange on a full sheet of fine grit on a glass tile. Be sure the flange is flat and smooth, including the edges of the bolt holes. Set it on the glass and check it with a feeler gauge.

Installation involves a thin even coat of black or red (coolant safe) RTV both sides of a new gasket (I use Fel-Pro*), left to dry is a good time to re-paint the housing and clean up the bolts & mounting surface on the intake manifold.

Next day I apply a thin coat of spray adhesive to one side (which will go against the housing), confirm the stat is pointed correctly against the flow (spring towards the engine/manifold), bleed hole up at 12 o'clock if applicable, staying in place on it's own, using a bit of hot glue if needed, then attach the gasket, spray adhesive side to the housing, then position the housing on the also-cleaned-and-flat port on the intake manifold and bolt manual says 15 ~ 22 ft. lbs. Too much will just warp it again, so resist any temptation to go nuts, but don't wimp out, either. Remember the housing is steel but the manifold is aluminum.

This is all left to sit another overnite, -before- adding coolant and wrapping things up. Sounds like a pain, but again, these housings luv to leak and can apparently smell fear, so don't be shy about showing yours who's the boss.

Good luck w/it.




Registered User
Thanks Ken!
Luckily I do body work on cars so I have access to all the tools to make it right. Cleaned sanded and lined it up good, in the morning I'll be doing the coolant and bleed the air out hopefully I have no more issues for a long time. This car better realize who's boss quickly!


Registered User
Jesus son of a b****! I had to take it apart 1 more time cause I didn't think I had the springs facing the engine side. Good thing I did cause I had it backwards! Back together and tomorrow a refill and drive.


Registered User
Whoever coined the phrase 3rd times a charm obviously didn't think about these tstat housings. Finally got it done without leaking and there was a difference between the spare housing I had and the one on the car. I'm thinking that was why it kept leaking, cause I did the exact same process twice only changing the housing and it doesn't leak this time. Hopefully you can see in the pics, but I think the previous owner maybe pryed on the housing?


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Registered User
Ouch, the one on the right doesn't look too good in comparison.
Also the flats having been rotated 90 degrees for some reason.


Registered User
Right It doesn't look good. Not sure what the previous owner did to it but it leaked no matter how good I sealed it. I should of checked it the first time

David Neibert

SCCoA Admin
Got tired of mine leaking and bought a reinforced one.



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Registered User
Where can I buy the reinforced thermostat housing? I noticed my car has not been cooling down as much as it usually does. It goes a little past the M on the gauge and drops down to the O, and now it only drops down to the R. I squeezed the top hose and it didnt feel like it had much coolant was passing through it, and the air blowing from the fan was hot. I suspect my thermostat is bad.


SCCoA Member
Billet assemblies used to be available from Ryan @ thunderbird SC Shop. They were pricey but looked great if you search you
may be able to find one somewhere.