Thermostat Housing gasket or no gasket

[TexasEd 191]

I have a 302-2V with original cast iron intake and cast iron thermostat housing. I pulled the old thermostat out and there was no gasket, just sealer. The bolts were very rusty.

 

I cleaned the sealer off both ends and sanded the mating surfaces shiny but there are still a lot of imperfections on the housing side.

 

Should I use the standard gasket with RTV or omit the gasket and use something like "The Right Stuff" instead?

[fordbsg 10]

new housings are cheap and available at your local parts house, I would use a new gasket and very little RTV. you dont want that stuff getting into the cooling system.

[Rsanter 152]

Gasket with a thin smear of black adhesive silicone.

Note, I say smear not bead

 

Bob

[jholmes217 65]

Gasket with a thin smear of black adhesive silicone.

Note, I say smear not bead

 

Bob

 

X2. Autozone sells a small tube of water pump and thermostat sealer.

[jnet4jt 10]

Also, if your housing has the plug next to the neck be sure to take out the plug and seal the threads with something, then reinstall. There is a good chance that it will leak if you don't seal it up.

[LindenBruce 27]

I have used straight silicone sealer many times without any problems. BUT. If you ever need to remove your thermostat in a pinch in the middle of no where because it failed, straight silicone won't allow you to make a seal when you replace the housing. So, as already suggested, a gasket with a smear of silicone on each side would prolly be best. B.

[Max Power 74]

Since our stats mount vertically, sometimes it is a little hard to hold them in that little shouldered shelf where they sit in the housing. I use both gasket sealer and a gasket. Put the thermostat in its proper location in the housing, apply light sealer and gasket, and let it dry. After it has dried, it should stay in place while mounting it on the intake. Apply light sealer on the other side as well.

 

Most leaks are caused by the stat slipping down while mounting if you don't follow these steps. (not mandatory, but better odds) Also, the stats slipping down and the installer not noticing is the primary cause for people snapping the tabs where the bolts go through. Back in the day before aftermarket ones were available, the boneyards would sell every good windsor stat housing they had.

[Brian Conway 264]

This is the one from my 428 motor but the same idea. I used ATV, black silicone, on the housing and install the gasket. Makes it a lot easier to center the gasket on the bolt holes. The thermostat goes in first, drill a 1/8" hole in it, the new gasket keeps it in place. ATV on the intake side and install. Brian

[TexasEd 191]

Why do you drill a hole in the thermostat?

[LoneWolf2U 136]

To allow air to purge when filling with coolant. Otherwise you need to burp cooling system of trapped air when warm.

[TexasEd 191]

Would that be necessary if I don't hook up the heater hose when filling the coolant?

Edited February 26, 2014 by TexasEd

[jholmes217 65]

Either way works. Allowing air to escape through the intake manifold heater hose elbow I think works better. I think it allows more air to escape.

Edited February 26, 2014 by jholmes217

[jwscarab 20]

I use an aftermarket housing with an o-ring. After installing the o-ring in the groove, I smear a light coating of right stuff on the housing.

 

As for the vertical mount, I loop a string around the t-stat bridge and my finger, holding the string snug till bolts installed. Then I cut the string and pull it off the t-stat.

[STL. Mark 11]

I have used this for years.