i have a 91 legacy 2.2 motor, thought it had ablown head gasket
because it kept over heating and because the antifreeze over flow tank
kept, well, overflowing. i put an obd I sniffer in the tank and checked
for hydrocarbons, bingo. so, i pull the heads, number 3 cylinder is
clean and the carbon is peeling off the valves, so i think to myself,
problem solved. replace the head gaskets fire it up and it runs fine,
for four hours. now it over heats but no more overflowing over flow.
what the heck is going on? ive replaced the thermostat twice, once
before and once after the head gaskets. still my coolant wont
circulate...

to make the car drivable, i cut the valve out of an old thermostat and
i can see the coolant circulating through the radiator. so its
driveable right now. any idea what could be causing a lack of
circulation with a functional thermostat in the car?