Radiator fanRadiator fan  - Cooling system - Checking and topping up fluids - General maintenance - Audi A5 Owner's Manual - Audi A5

The radiator fan can start running spontaneously.

The radiator fan is driven by the engine via a poly V-belt. The speed of the fan is varied by a viscous clutch according to the temperature.

There is also an auxiliary electric fan, which cuts in automatically whenever the temperature of the coolant and the engine compartment rises above a certain level.

The auxiliary fan can continue to run for as long as 10 minutes after stopping the engine Ц even after the ignition is switched off. It may also start running suddenly  after a while if Х residual heat raises the coolant temperature, or
Х the hot engine compartment is additionally heated up by the sun.

When working in the engine compartment be aware that the radiator fan may WARNING

When working in the engine compartment be aware that the radiator fan may start running suddenly Ц risk of injury.