what is the purpose of a radiator cap?
<answer> The purpose of the radiator is to radiate heat away from the engine by moving the mixture of coolant and water though passages in the engine block and then running it back through the radiator where the heat is transferred into the air. <context> Without a radiator your car will weigh less and go faster. All joking aside the purpose of the radiator is to radiate heat away from the engine by moving the mixture of coolant and water though passages in the engine block and then running it back through the radiator where the heat is transferred into the air. The coolant carries the heat of the engine up to the radiator. The radiator is either cooled by air flowing through it from you driving or when you are stopped and it starts getting hot the fan will kick on to cool it. If you drive in hot weather or if you car is stationary for a long time running it could overheat.