My pt cruiser only overheats when it idils and when you get it up past 30 it cools down. is there any cause for this besides a head gasket?

 

low coolant level?
bad thermostat?

 

radiator fan not working low coolant your still low at no matter what speed you at. Same with a thermostat its still broken or stuck closed so would not make any difference what speed your going. A fan is designed to move air over the radiator when the car it self is not moving to remove the heat from the coolant.

 

in the old days (90s!) we used to pull the coolant temp sender wire off while the engine was running, which would automatically turn the fan on since the computer would see the sensor failure and go into "default" protection mode.
no idea if that works still or not on NGC3 cars, but it could be a quick way to test if at least 1 of the fan circuits is working.