I have had the gases checked in my overflow tank (which boils short distances) and also over heats.
Two different mechanics tested the gases and said it's not the head gasket but yet it still boils in the overflow tank.
It also overheats when the temperature outside starts warming up, this winter I could drive it anywhere and it didn't over heat but now that spring is here its is starting again.
My husband has changed the thermostat twice and radiator cap. I also had the radiator fan replaced.
Do you have any suggestions as to why it's overheating?