8BA leaky thermostat housings?

[36tudordeluxe]

Was running without 'stats and temp. would only get in the 160°-165° range now that weather is cooler; my understanding is low operating temp. promotes sludge buildup. Without the 'stats no leaks around the bottom of housings but since installing 'stats it leaks between housing bottom & gasket. I cleaned mating surfaces & used new gaskets & silicone sealer; any ideas to solve this problem?

[51 MERC-CT]

Thermostats not seated in their recess in the gooseneck.

[36tudordeluxe]

Originally Posted by 51 MERC-CT

Thermostats not seated in their recess in the gooseneck.

Checked that & they are seated, thanks for responding.

[tubman]

Wrong thermostats?

[El Rat]

Not flat or the stat is not captured or housing is cracked or bolts bottomed out.

[36tudordeluxe]

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Got the right 'stats, they fit perfectly, mating surfaces are flat & clean, no cracks in the housings........but am wondering as El Rat suggest about the bolts being too long as they are aftermarket. Will investigate. Just did a quick check & bolts only project 3/8" beyond lip of housing.
Wonder if there is a specific torque setting for the housings; I'll try again when I get the new gaskets. I noticed with the last set of gaskets, one side of the gasket has a peel off that leaves one side of the gasket sticky, would it make any difference which way the sticky side faces?

[flatford8]

Whats aftermarket the bolts or the housings? Do they both leak?....::Mark

[19Fordy]

Replace the bolts with studs using sealer and your problem will go away.

[36tudordeluxe]

The bolts are aftermarket SS & housings are aluminum; I didn't have a problem until I installed 'stats.

[36tudordeluxe]

Originally Posted by 19Fordy

Replace the bolts with studs using sealer and your problem will go away.

Will pick up some studs, do you mean "Loktite" for the sealer?

[cmbrucew]

Thermostats facing right direction, seated correctly with a good gasket should not leak at six or seven pounds.
Bruce

[tanner]

I experienced the same problem and found that stat had slipped down slightly and lower edge was out of the grove. You may need to center stat with your finger while tightening.

[Talkwrench]

Bob, Go buy yourself some gasket material, its usually black for water. make sure its .060 + cut your own gaskets. use something like a non hardening sealant [like permatex No.3 here in Aust] don't over tighten, and after the first warm up just tweak it up again. Also wipe the inside of your hoses as you put them on with the non hardening sealant. You have checked the surfaces are flat, and the bolts are too long so that's done ...

[36tudordeluxe]

Okay, here's picture of 'stats installed in housings; they're held in with a couple dabs of silicone to keep them centered. Will use Permatex as I have some instead of the silicone I was using on the mating surfaces. Thanks everyone for the help.

[donald1950]

just use grey silicone sealer from napa and cover both sides of the gasket first (this is messy but gurentees the gaskets are covered with sealer) and then put the gasket on the housing with the stat in place and then set the housing on the head. by useing studs it will slip right on and no wiggling the housing to locate bolts that might move the gasket or stat. be liberal with the sealer and just wipe of the excess after the nuts are tightened in place. you might also try running teh housings accross some 600 grit wet or dry sand paper taped to a sheet of glass to be sure the mating surfaces are flat. you might want to use two of the same brand of stats also and drill a 1/16 air bleed hole on each stat to let the air out during fill up with water

[Talkwrench]

Bob I recon half the problem is those gaskets you get with the peal off sticky side.
I don't think they are a good idea.

[deuce_roadster]

With the housings and stats like in the picture, put a straight edge across and see if the stat sticks down past (lower) then the flat on the housing. If the housing was flat filed or milled too much, the recess might not be deep enough anymore. That could explain why they don't leak when the stats are not there. Maybe new housings would have a deep enough recess to seal properly.

[19Fordy]

Originally Posted by 36tudordeluxe

Will pick up some studs, do you mean "Loktite" for the sealer?

I would first try BLUE Locktite on the threads and try that. That way I could always remove the stud if it leaks by "double nutting" it. This is probably one of those times you may have to try various remedies. You will succeed.
Can you tell now if it's leaking at the stud or the gasket surface?

[36tudordeluxe]

Problem solved, for some reason the non-hardening #2 Permatex worked. BTW, temp. is right where it should be with the 'stats installed.

[Talkwrench]

I think your #2 [in USA]must be our # 3 [Aust], because I couldn't get it a NAPA when I was fixing a mates car when I was over.
Good to see it fixed

[36tudordeluxe]

Originally Posted by Talkwrench

I think your #2 [in USA]must be our # 3 [Aust], because I couldn't get it a NAPA when I was fixing a mates car when I was over.
Good to see it fixed

I think you're right because I can't find #3 here as you suggested, thanks for the tip.

[russcc]

I used studs in the 8RT and they sure saved a lot of hassle trying to line up the capscrews and thermostat at the same time.

[36tudordeluxe]

Originally Posted by russcc

I used studs in the 8RT and they sure saved a lot of hassle trying to line up the capscrews and thermostat at the same time.

If I ever do it again, that's what I'll do.

[my4dv8]

I have found that a couple of dabs of sealant on the housings to hold the stats in place works a every time now , after having one slip out and crack an aftermarket housing.

[flatjack9]

I do the same thing. If the housing needs sealant to stop a leak, something is wrong with either one of the surfaces. No sealant should be needed.

[jimvette59]

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Originally Posted by 36tudordeluxe

Problem solved, for some reason the non-hardening #2 Permatex worked. BTW, temp. is right where it should be with the 'stats installed.

We've been using #2 non hardening Permatex for ever on those types of applications way before all the colored silicone stuff came out. It always worked for me. JMHO