I wouldn't worry about the tstat rattling around, I bet the enough of the gasket will hold it in place.
I ended up using the JB Weld around the outside of the housing and on the gasket seat area. I ran the car in the shop and then took it on a 10 mile ride with no leaks. Just one thing... when I started with this, I was using the gaskets made by Stant . These have an adhesive on one side of the gasket. My leak was much worse with this gasket. Not sure if that side with the adhesive seals very well. I switched to a FelPro gasket and the leak was really, really minor (a small drop after a day). Thanks to all for the help.
some thermostats are supplied with a rubber/vinyl/composite ring that fits around the outside diameter of the tstat, like this one7710]. Maybe the housing you have is intended to use a tstat like this
I always use silicone sealer, I put a small amount on my finger and rub it on both sides of the gasket, seals good, I've never had any problems.
Know I am late on this thread but I always,always use 2 gaskets on thermostat and water pumps,no sealer of any kind and no leaks!
Found these as an option, I have not tried one yet but will. tonysparts.com
![[Image: Banner-ThermostatHousing.jpg]](http://tonysparts.com/Images/banners/Banner-ThermostatHousing.jpg)
67r/t4speeder Wrote:Found these as an option, I have not tried one yet but will. tonysparts.com
I just saw this yesterday, funny I never noticed a casting # on those.
Racer Brown Wrote:I just saw this yesterday, funny I never noticed a casting # on those.
Usually covered up with paint