You probably have air trapped in the heater core. That's why we usually use vacuum to fill the cooling system.

Answered by Wrenchtech (expert)
14,708 answers provided

How do I get the airpocket out

Response from jnurse
3 questions asked

It should work out on it's own.
With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch.
If you find that they are both too hot to hold, then the heat in that vehicle is controlled by a blend door that regulates heated air flow. it is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.
If they are both not too hot to hold on to, then you either have a restricted heater core or the system is not completely full and getting air pockets for some reason.

Answered by Wrenchtech (expert)
14,708 answers provided