The cooling system works by sending a liquid coolant through passages in the engine block and engine heads. The parts of the cooling system is the 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 cap to control the pressure in the system, some plumbing consisting of interconnecting hoses to transfer the coolant from the engine to the radiator and hot coolant from the car's heater system where hot coolant is used to warm up the vehicles interior on a cold day.
The radiator core is usually made of flattened alluminium strips that zig-zag between the tubes. These fins tranfer heat in the tubes into the air stream to be carried away from the vehicle. Mounted on the back of the radiator on the side closest to the engine is one or two electric fans inside a housing that is designed to protect fingers and to direct the air flow. These fans are there to keep the air flow going through the radiator while the vehicle is going slow or is stopped with the engine running.
If the car has air-conditioning, there is an additional radiator mounted in front of the normal radiator. This "radiator" is called the air conditioner condenser, which also needs to be cooled by the air flow entering the engine compartment. As long as the air conditioning is turned on, the system will keep the fan running even if the engine is not running hot. This is because if there is no air flow through the air conditioning condenser, the air conditioner will not be able to cool the air entering the interior.
The Air-Conditioning condenser fan is designed to keep the condenser cool so that it can continue to effeciently convert the gas into liquid and keep the Air-Conditioning system operating correctly.
A defective fan can cause problems with the entire Air-Conditioning system. Usually the vehicle will display a few symptoms when the condenser fan has failed such as the car overheating while idle, a burning smell in the car and lukewarm air coming from the Air-Conditioning vent. If you need to replace this part, ensure that you buy the right aircon radiator fan for your car's air conditioning system.