When I replaced the water pump on my '60 Chevy it did the same thing. I would let it cool down, empty some water out of the rad, fill some more water in the top of the rad, and after a few times it stopped overheating. I don't know if it was air in the rad or not, but it worked.
Oh, while doing this process, I turned on the heater full blast to make sure coolent was circulating thru the heater core and push out any air. And I would start the engine and rev it up a little to push the water.
Last edited by Iron Clad; 03/07/2010 5:02 AM.
