never have had much heat from the heater of my 62 544 took it all apart took out the mouse nest between the blower and the cab and thought that was it, my discovery is the water doesn't circulate to the core from the pump, the heater core hoses never get hot, even after the thermostat opens I assume the pipe running parallel with the block from the pump would feed the core, when I took the core out it had a little anti- freeze in it and I blew thru it seemed fine do you have to bleed the air? I have a inline after mkt valve in 1 line but it is wide open, ant thoughts would be appreciated 2tired