I am not sure where mine is coming from. I am going to replace the housing first, and see what happens. I am waiting on my local independent parts guy to get the part in today. I wud like to drive the car this evening. I replaced the water pump a few months ago and did'nt see any signs of a leak arnd the time cover. I shud have replaced the housing then; easier w/ the ac bracket not in the way. My Bad.
on mashori's car he had problems getting his t-stat housing to seal. it turned out the performer rpm intake had less surface around the bypass hole for the t-stat gasket to seal. also we found that the aftermarket t-stat housings we were getting all had the bypass hole further out towards where the lack of material was. we got a new factory ford housing and gasket and it lined up better with the intake and sealed with no problems.
The housing I replaced had an O-ring. I was not aware it was/had the ring until today when I removed it. I was placing a gasket on top of the ring. Don't know why I did'nt see the ring; I had the housing off 3 times prior. I did install another AM unit w/o the ring - it came w/ a gasket. Anyway, I think it may resolve the issue. Time will tell. If not, I will try the Ford unit.
I have one on my 71 comet never had that problem , i just made sure that the surface was cleaned and the old gasket was off that is the key a clean surface.
I would pressure test the system to see exactly where the leak is. Sometimes the leak is the radiator or bypass hose not being tight enough and looks like it is coming from the thermostat housing.
I've also had cold engine seepage come from the hoses, sometimes through the cords of cheaper or old hoses as well. It would always dry up where you couldn't tell where it was coming from and passed pressure tests all day long.
