svtlover
CEG'er
This isn't a "how to" R&R the thermostat; it's a "what not to do". DO NOT buy an aftermarket thermostat! Get the Ford part, even though it costs more. I learned this the hard way after my tech pulled every last root of his hair out (not to mention my own frustration) trying to figure out a slight overheating problem. If your temp gauge just won't stay "in the middle", make sure your thermostat was never replaced with an aftermarket unit. It may not be your radiator or a flow problem. The Ford thermostat has a hollow tube with holes in it. The aftermarket one we found did not. Long story short, the aftermarket design is not hollow and will not work right with the return-line system that Ford built. They cut the flow too much, which causes the car to run warm. Hope this helps someone out there.