". Coolant should be running through the heater core at all times.". Yeah, but it's not. No heat in car. Thanks for the input, but none if it helped.
As far as why Ford put it there, it's the only car I have ever worked on, and I have worked and owned far too many too remember, that has a thermostat on the bottom. A properly designed system would not have to worry about putting too much cold water into the system. That's what the thermostat is supposed to do, with a properly sized radiator, and fans. I specialize in Mercedes Benz's mostly, and I've never seen such bad engineering. There is air in the line somewhere, I can hear it gurgling, and I get no Heat from a previously, unit the thermostat went bad, a heater that would cook you. The removed coolant looked new. This car was always maintained by my Mom.
I am not a "fanboy" of any car, they are machines, with their systems, some good, some not so good. There is air in the system. I guess I will have to drain a start again.
I wanted to install a flush kit. Does anywhere know where to put one of those "T's" in the system? I have"burped" much air out the car. The only thing left to think is I may be getting pressure from a bad head gasket, an internal leak, though there is no discoloration and the pressure does not reach that high, and one would thing this would be constant. It only overheats when pressurized. I idled the car for 1/2 half hour, and it runs just under the center of the Temp gauge, like it did before. Only putting the cap back on causes things to change, and I still get to heat no matter what. I can hear the gurgling and the thermostat snap open and closed, as if there were steam down there. Especially after shutting off. Massaging the hoses does nothing, but I can feel the air in there. Any picture showing where to put a "T" or where they be a bleed valve would be most helpful. Please take no comments as pejorative of Ford, bad engineering by any company is bad engineering. I've seen it in every model car I have ever worked on. I have blueprinted too many engines.
I am going to try and find and pinch of the heater core bypass core, hopefully this will fix it.
If not, I will drain and start all over again. Nothing else left to do.