Almost all automobiles employ a, liquid cooling system for their engines.
The cooling system is made up of:
- passages inside the engine block and heads
- a water pump to circulate the coolant
- a thermostat to control the temperature of the coolant
- a radiator to cool the coolant
- a radiator cap to control the pressure in the system
- interconnecting hoses to transfer the coolant from engine to radiator (and also to the car’s heater system where hot coolant is used to warm up the vehicle’s interior)
So, a cooling system works by, sending a liquid coolant through passages in the engine block and heads. Consequently, as the coolant flows through these passages, it picks up heat from the engine. The heated fluid then makes its way, through a rubber hose to the radiator, in the front of the car. As it flows through the thin tubes in the radiator, the hot liquid is cooled by; the air stream entering the engine compartment, from the grill in front of the car.
Finally, once the fluid is cooled, it returns to the engine, to absorb more heat. The water pump has the job of keeping the fluid moving through this cooling system.
For operation at temperatures below 0 °C (32 °F), it is necessary to prevent the cooling system from freezing.
This is usually done by adding some compound, such as ethylene glycol; to depress the freezing point of the coolant. So, by varying the amount of additive, it is possible to protect against freezing of the coolant; down to any minimum temperature normally encountered. Coolants contain corrosion inhibitors; designed to make it necessary to drain and refill the cooling system, only every few years.