Hi guys Need help. I just put in a new Koyo radiator and now the car overheats when i put the radiator cap on. I drive for 20 to 30 min and if I punch it a few time the Temp gradualy rises didnt think much of it. first I thought It could be an Air Bubble in the circuit. Is the a nut of some sort to purge the cooling system? I Changed the Raidator cause the original cracked and I lost all the water will driving. Yes it overheated. Could I have a headgasket problem? Im so f**ked.