[Lucalare]

clogged heater core maybe? If it's not an air pocket (which is more likely), try flushing it.

1. disconnect the hoses from the heater core (passenger side of the firewall, on the engine side, there should be two hoses right next to each other), use a channel lock with light pressure and a twisting motion to take the hoses off.
2. hook separate hoses up to each of the connectors on the heater core that aren't connected to anything.
turn on your hose, kink it, and hold it flush up against the end of one of the hoses, then unkink it and stomp on it where it's down on the ground. be sure the other hose is running outside the engine bay.
3. Do the same to the other hose. keep back and forth until nothing but clean water is coming out, and maybe another cycle just to be safe.
4. hook the original hoses back up, start it, get the coolant level right, then test it.

Be careful because the heater core is made of aluminum, and the little nipple the hoses connect to crush really easily.