Postby VStar650CL » Tue Jul 26, 2022 12:06 pm
Check balance on your fan, even a tiny amount of imbalance out at the ends of the blades becomes very exaggerated at engine speeds and will cause repeated clutch failures.
I don't know where you're located, but counterintuitively, the more work a viscous clutch does, the longer it will probably last. That's because the speed differential between the pump and fan sides of the clutch is greatest when the engine is cold and the fan is freewheeling. Once the clutch heats and the fan grabs, the bearing surfaces inside the clutch do far less work. So as a pure mechanical matter, cold climates are clutch-killers (not that you can necessarily do much about that).