so today my car started to overheat there is no coolant leaks or anything the fan turns on
the only way the temperature stays close to normal is if the heater is on full blast
the thermostat has never been replaced so im thinking its possibly that and the little return line that goes from the housing to the overflow tank is spitting coolant into the tank alot when the fan turns on

 

You can pull the thermostat out and test it in a pot of water on the stove, assuming you have a thermometer to check the water temperature. What I usually do if I suspect the termostat is just remove it and see if that fixes the problem.

Don't run the car if it's overheading. You'll blow a head gasket real easy.

 

thanks