F 450 2WD Super Duty V10-6.8L VIN S (1999)
Fan Clutch: Testing and Inspection
Maximum Speed Fan Clutch Requirement Test
1. Perform Steps 1 through 5 of the Fan Clutch Test-Minimum Speed Requirement.
2. NOTE: The temperature should be above 96°C (205°F) for maximum fan speed.
Block off areas on each side of the radiator in the engine compartment and the front of the radiator grille. This will raise the temperature of the air
striking the fan clutch and should cause the fan blade to operate at maximum speed.
3. Place the climate control function selector switch in the MAX A/C position and the blower motor switch in the HI position.
4. Adjust the strobe to 3000 rpm.
5. WARNING: To avoid the possibility of personal injury or damage to the vehicle, do not operate the engine until the fan blade has been
first examined for possible cracks and separation.
Start the engine and adjust the engine speed until the strobe light flash and the water pump pulley mark are synchronized.
6. Aim the strobe light at the fan blade retaining bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade bolt (the
fan blade appears to stand still).
7. If the fan blade speed is less than 2300 rpm, replace the fan clutch.
