RAM 2500 Van V8-5.9L VIN Z (1997)
It is normal for fan noise to be louder (roaring) when:
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The underhood temperature is above the engagement point for the viscous drive coupling. This may occur when ambient (outside air
temperature) is very high.
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Engine loads and temperatures are high such as when towing a trailer.
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Cool silicone fluid within the fan drive unit is being redistributed back to its normal disengaged (warm) position. This can occur during the
first 15 seconds to one minute after engine start-up on a cold engine.
LEAKS
Viscous fan drive operation is not affected by small oil stains near the drive bearing. If leakage appears excessive, replace the fan drive unit.
