- When testing viscous fan drives it is most effective at an ambient
air temperature of 80° (26.7° C) or higher. (If checked on a
dynamometer, ambient temperature should be at least 65-70 degrees)
- Kysor
fan clutch friction linings can be replaced without taking the clutch
off the vehicle. This reduces lining service to about ten minutes.
- Viscous fan clutch speed should be at least 85% of pulley speed after engagement.
- Fan
clutch control problems causing excessive cycling or low air pressure
are the most common causes of clutch overheating and lining failure.
- Typical
reasons for a/c clutches to slip or fail are; high head pressure( and
missing or faulty pressure protection switches); oil, grease or
antifreeze spilt on friction surfaces; low voltage or bad connection to
coil; miss alignment or over-torqued belt.
- Cracked/broken belt tensioner arm indicates a tensioner allowed to snap back against stops or incorrect installation/removal.
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