I am a mechanic and having problems fixing this vehicle.  AFter replacing head gasket car seems to overheat.  I have replaced water pump, thermostat, water control valve.  Any suggests would help.
 Doug.
Did you purge the air out of the cooling system? Your manual should have a procedure to do this. Also, I like to drill a 1/8th inch hole in the flat plate of the thermostat as an air-bleed.Just to be on the safe side.
also make sure you are using the right antifreeze for your make and model.