K 1500 Truck 4WD V6-4.3L VIN W (1997)
Fan Clutch: Testing and Inspection
Noise
WARNING: To help avoid personal injury or damage to the vehicle, a bent, cracked, or damaged fan blade should always be replaced.
NORMAL CONDITIONS
Fan noise is sometimes evident under the following normal conditions.
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When the clutch is fully engaged for maximum cooling.
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During the first 15 seconds to one minute after start-up until the clutch can re-distribute the silicone fluid back to its normal disengaged
operating condition (after overnight settling).
ABNORMAL CONDITIONS
Fan noise or an excessive roar will generally occur continuously under all high engine speed conditions (2500 RPM and up) if the clutch assembly is
locked up due to an internal failure. If the fan cannot be rotated by hand or there is a rough grating feel as the fan is turned, replace the clutch. Refer to
"Fan and Fan Blade Clutch Replacement" in this section.
