Overheating

Low coolant, the water pump more than likely, or the thermostat. I would plan on having the water pump replaced along with the thermostat. The impeller on the water pump disintegrates so it can't circulate the coolant.

Sounds like the thermostat is stuck closed, causing the overheating problem, since water doesn't circulate through the heater core, you don't get the hot air on the heater

Did you ever find what the problem was? I would also check both the water pump tensioner and also the purge line for any clogging. I've have seen both a clogged purge line and I've had to replace the water pump belt tensioner which caused an overheat condition.