A blown head gasket is a possibility… The “air” in the radiator could be combustion gasses…This will blow the coolant out of the radiator and into the overflow tank and it won’t be drawn back in…
A blown head gasket is a possibility… The “air” in the radiator could be combustion gasses…This will blow the coolant out of the radiator and into the overflow tank and it won’t be drawn back in…