[GTP Dad]

It sounds like you may have air in the system. Getting hot quickly like that even at idle indicates there is a problem with the coolant circulating. Try opening the bleeder screw on the top of the thermostat housing and see if you get air or coolant. If you get air continue to bleed until all the air is out. Also make sure to turn the heater on high while doing this. Sometimes air gets trapped in the heater core and causes these issues.