Cooling system fan (Scorpio 1)

The cooling fan drive consists of two important parts - an electromagnetic clutch and a friction clutch. The electromagnetic clutch is driven by a V-belt and rotates on an axis that rests on two ball bearings mounted in the lug of the timing cover. At the front end of this axis is a ball bearing on which the friction clutch with the fan blades rotates freely. There is an air gap between the electromagnetic and friction clutches if the engine temperature does not exceed 71°C. When the coolant temperature rises above 85°C, a sensor mounted on the radiator supplies voltage to the carbon contact brush and, through the contact ring, to the electromagnetic coil. Under the action of the magnetic field, the friction clutch is attracted to the electromagnetic one, and the fan blades begin to rotate at the speed of the pulley. When the coolant temperature decreases, the electromagnet is switched off, the gap is restored and the fan blades slow down, rotating only under the influence of the air flow and inertia.

For the clutch to operate properly, the drive belt tension must be correct, the electrical sensor must be in good working order, the carbon brush must not be worn out, and the contact ring must be clean.

The gap between the fan and the clutch bushing is 0.5 mm on a cold engine. Before checking the gap, remove the fan blades by unscrewing the fastening nuts. Measurements are taken with a feeler gauge at several points around the circumference. To make adjustments, loosen the lock nuts of the adjusting bolts and, by rotating them, set the required gap.