Sidekick JSS 4D Hard Top 2WD L4-1.8L (1997)
Fan Clutch: Description and Operation
COOLING FAN CLUTCH
Fluid is enclosed in the cooling fan clutch and at its center front, there is a bimetal whose thermal reaction and the engine speed control the cooling fan
speed. The clutch is installed to the cooling fan pulley, so that the cooling fan operates at approximately the same speed as the water pump shaft
regardless of the air temperature at the front of the clutch when the water pump shaft turns at low speed (when the engine running at idle speed). The
relation between the temperature detected by the fan clutch and operation of the fan clutch is as follows. While the fan clutch detects a temperature
lower than 50°C, it remains OFF and the fan revolution speed is constant (500 to 800 r/minute (rpm) regardless of the engine speed. As the
temperature reaches 50°C to 70°C, the fan clutch turns ON gradually and the fan revolution speed increases. A temperature exceeding 70°C causes
the fan clutch to turn ON and the fan revolution speed to increase in proportion with the engine speed. Once the engine speed exceeds 4,000 r/minute
(rpm), however, the fan revolution speed becomes constant (2,250 to 2,550 r/minute (rpm).
NOTE: Do not disassemble fan clutch.
