Thermostat Gasket

I tried tightening it down from light to too much, didn't matter. Sanded housing flat, filed the intake, never had these issues that I remember from working at a garage for awhile in the late 60's, early 70's. The o-ringed housing is the fix, I have never had to mess with the damn thing since. Torqued in inch lbs, don't remember how much, not out in the garage.