Fan Clutch Operational Test

WARNING: Do not operate the engine until the fan has been first checked for possible cracks and separations.

1. Run engine at a fast idle speed 1500 RPM until normal operating temperature is reached. This can be done more quickly by blocking off the front of the radiator with cardboard.

NOTE: Regardless of temperatures, the unit must be operated for at least five minutes immediately before being tested.

2. Stop engine and, using a glove or a cloth to protect the hand, immediately check the effort required to turn the fan.
- If considerable effort is required, it can be assumed that the coupling is operating satisfactorily.
- If very little effort is required to turn the fan, the coupling is not operating properly and should be replaced.

Bi-Metallic Coiled Spring Removal:

3. The clutch fan may be tested while the vehicle is being driven. To check, disconnect the bi-metallic spring, and rotate it 90° counterclockwise. This disables the temperature-controlled, free-wheeling feature and the clutch performs like a conventional fan. If this cures the overheating condition, replace the clutch fan.