I tried the bike pump method for purging air from the cooling system.  Seemed to work great.  I tried it because my 84 still runs hot unless the heater is on full blast.  Everyone says air in the cooling system.  It's getting too hot outside to be hot inside!  I have felt the radiator when the van is running hot and it seems cool and the electric fan doesn't come on. I thought I may have a plugged radiator but coolant came out of the radiator from the bleeder valve with a slight pump.  Does this leave the water pump as the prime suspect for overheating?  Thanks Jeff