A cars radiator is a central part of the engines cooling system. Responsible for removal of heat from the engine coolant, the radiator system cools the liquid by allowing fresh external air to pass over a network of thin pipes, losing heat to the atmosphere.
In between the radiator and the bonnet grille is another key component of the radiator system - the radiator fan. This fan blows fresh air across the radiators cores helping to cool the coolant, which is especially important when the car is slow moving or at a standstill.
Most modern cars use an electric motor driven fan, which is controlled by a radiator temperature switch. This switch regulates when the electric fan is on or off.
If your car is overheating in slow moving traffic you should check your <Model radiator temperature switch as this may be malfunctioning and failing to engage the fan.