Variable Speed Cooling Fans: Testing

In cases of engine overheating or insufficient air conditioning proceed with the following:

1. Start with a cool engine to ensure complete fan clutch disengagement.
2. Cover radiator grille sufficiently to induce high engine temperature.
3. Start engine and operate at 2000 RPM, turn on air conditioning if equipped.
4. A fan roar will be noticed when the fan clutch engages.
   NOTE: It will take approximately 5 to 10 minutes for the temperature to become high enough to allow engagement of the fan clutch. While operating engine under these conditions, observe temperature light to prevent overheating. If hot light comes on, remove cover from radiator grille.
5. As soon as the clutch engages, remove the radiator grille cover and turn the A/C off to assist in engine cooling.
6. After several minutes the fan clutch should disengage. This can be determined by a reduction in fan speed and roar. If the fan fails to function as described, it should be replaced.
   Fig 1: Thermostatically Controlled Fan (Shown with Stamped Face and Bi-metal Coil Spring)

   Courtesy of NOT AVAILABLE