You know everyone keeps saying water pump, and I a no contour expert yet but I think you might have a bad thermostat. It keeps the coolant in the motor until it heats up and then opens up to let it circulate to your radiator and heater core. You should check it before you take off the water pump again. Take it out and take it in the house. I put them in a bowl of really hot water and visual look to see if it opens.
Someone please correct me if I am wrong.
thanks Joe
