What device cools a cars engine?

Answer 1

Hi,

The main device that cools a cars engine is the radiator, however to state that is not exactly true. Car engines run hot, and this is to increase the efficiency of the engine. The thermostat in the engine, and the temperature probe in the radiator are all set to keep the engine at a predetermined factory set temperature. The cooling fan behind the radiator will only work when the temperature of the engine goes over the predetermined temperature, to bring it back down. Notice the word temperature not cool in the explanation. Like the human body temperature is monitored.

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There's some inaccuracies in the above answer. The radiator does not directly cool a car's engine - it cools the coolant which passes through it.

The whole cooling system is the "device" you're referring to. That would be the water pump, radiator, hoses, and thermostat. When the thermostat reaches a predetermined temperature, it opens up and allows coolant to flow through the motor. The most basic law of thermal dynamics is that heat always flows to a cooler object. Thus, the heat from the engine flows to the coolant in a heat exchange. The heated coolant then is cycled to the radiator, where another heat exchange takes place - this time, the heat from the coolant transfers to the air which is passing through the radiator. This is why it's important to keep air flow to the radiator (as well as the air conditioning condenser) unobstructed.

Additionally, the airflow over the motor created by the engine fan also creates a heat exchange, where heat from the engine is transferred to the cooler air flowing over the engine.