I asked for help a few months ago concerning no heat on my 1978 Ford Granada. I did replace the thermostat but still had no heat. I then connected my compressor to the hose to the heater core and blew it out. There is no blockage or leaks. Air came out of the return hose freely. I am going to dismantle the dash to get to the head and cables next. What I want to know is: 1. Is water always circulating through the heater core? If not, what allows the water to circulate? Turning the temperature adjust lever in conjunction with the selector lever? 2. Can the problem just be the core itself? Both hoses into and out of the core are hot and the air circulation does change when I move the selector lever to vent, ac, high/low, heat, and defrost.
Thank you