My old engine is running semi-well and I have no real complaints. I have recently installed new thermostats and the install made me want to ask a question. The thermostats install at the top of my heads inside a small cover, diaphragm, and four bolts. The thermostats thread in to the diaphragm, then the cover goes on top, screwing into the top of the head opening. When I screw the thermostat in to to diaphragm, there is room to thread in or thread out. If I do not completely screw the thermostat in, it will push its tapered nose in to seal a round opening inside the head. Do I thread the thermostat all the way down against the diaphragm, which would leave a gap between the tapered end of the thermostat and the inside of the head? Complicated, I know. Right now I have them threaded down tight against the diaphragm, which I think creates a gap between the thermostat and the circle inside of the head. Any help is greatly appreciated.
