Viscous Fans

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.

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 (20-30%). 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 (80%). This increases airflow through the radiator ensuring the system temperature is controlled.



Product Overview


Feature points

  • 48 part numbers covering 95% of the UK car parc.
  • 2 part numbers complete with cooling fan blades.
  • Full competitor and OE x-reference.
  • European and Asian application references.
  • OE matching quality.
  • 12 months / 12,000 mile warranty.

Replacement reasons

  • Surface oxidation can affecting 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.