Skylark V6-3100 3.1L VIN M SFI (1996)
Fan Clutch: Description and Operation
Fig. 1 Typical Variable Speed Cooling Fan
Fig. 2 Variable Speed Fan W/Flat Bi-Metal Thermostatic Spring
Fig. 3 Variable-Speed Fan W/Coiled Bi-Metal Thermostatic Spring
The fan drive clutch, Fig. 1 , is a fluid coupling containing silicone oil. Fan speed is regulated by the torque carrying capacity of the silicone oil. The
more silicone oil in the coupling, the greater the fan speed; the less silicone oil, the slower the fan speed.
Two types of fan drive clutches are in use. On one, Fig.2 , a bi-metallic strip and control piston on the front of the fluid coupling regulates the amount
of silicone oil entering the coupling. The bi-metallic strip flexes outward with an increase in surrounding temperature and allows a piston to move
outward. The piston opens a valve regulating the flow of silicone oil into the coupling from a reserve chamber. The silicone oil is returned to the
reserve chamber through a bleed hole when the valve is closed.
