97 Lincoln Mark 8 overheating after changing thermostat cannot get air out
Bleed the cooling system by parking the car on a slope facing uphill. Remove the radiator cap when the car is cool and idle the car until the air bubbles are removed, top off the coolant and you should be good to go.
I've done that and I still can't get it to stop overheating and now I have no heat
Did you install the thermostat upside down?
The thermostat will only go in one way
Remove the highest hose in the cooling or heater system to get air out. No heat is a sure sign of a heater core full of air.