The Viscous Fan, otherwise known as a Fan Clutch, is a thermostatic device commonly used in many Asian and European RWD vehicles. This intelligent component improves engine efficiency by regulating the RPM of the engine fan and cool air supply.
BG Automotive has launched a range of 60 Viscous Fan part numbers, covering 95% of the UK car parc, including part numbers available with cooling fan blades.
References are available for both European and Asian applications and all are OE matching quality and come with a 12 month warranty.
Most Viscous Fans consist of two semi-independent rotating components, controlled by a bimetal sensor. When the sensor is cold, the components work independently; rotating at a lower RPM than the Water Pump. The Fan remains in a disengaged state, conserving fuel consumption.
When the bimetal sensor heats up in reaction to the engine’s demands, it expands, enabling the two semi-independent components to rotate closer to the Water Pump’s RPM. This increases airflow through the radiator ensuring the system temperature is controlled.
A Viscous Fan could become permanently engaged or disengaged due to the following reasons:
- Surface oxidation can affect the bimetal sensor and cause it to stick.
- Silicone fluid leaking from the component will influence Fan efficiency.
- When the bearings inside the Fan fail the component will stop working.
If the Fan Clutch is faulty, the air conditioner’s condenser (directly in front of the Radiator) cannot be cooled. This effects the whole air conditioning system. Fan failure will result in noise and vibration at high speeds increasing fuel consumption and may cause overheating.
