The car radiator ensures that the engine does not overheat while driving. The radiator plays an essential role in cooling internal combustion engines. In such engines there are up to 4,000 fuel explosions per minute, each generating a temperature of up to 1,500 °C. The coolant, circulating through a cooling jacket, cools the engine block and internal engine parts.

The circulating coolant absorbs the heat of combustion. Flowing through the radiator, it exchanges heat with the surrounding air.

The water pump is usually powered by the engines timing belt or auxiliary belt. Its job is to circulate the coolant through the system, if the pump fails the engine will overheat causing damage to other engine components with the high temperatures.

The thermostat is the door between the engine and the rest of the cooling system, It stays closed during engine warm up and opens at a set temperature to allow the hot coolant flow to the radiator to be cooled. 

The cooling fan is used to force cold air through the radiator to cool the coolant when airflow is low such as when stopped in traffic. It is controlled by the engine computer.

The coolant temperature sensor detects the engine's operating temperature and relays it to the engine computer so it can make decisions on fuelling strategy and turn the cooling fans on when a set temperature is reached. on modern vehicles there are usually multiple coolant temperature sensors around different parts of the cooling system.

The heater matrix is located inside the passenger compartment and is a part of the heater blower unit behind the dashboard. When the thermostat has opened the hot coolant from the engine flows  through  the heater matrix and when the heater control is set to hot the fan blower motor forces air through the fins  of the matrix and heats the air that comes through the dashboard vents.