Should a Viscous Fan Spin Freely?

The fan should move freely by hand when the vehicle is off. Any strong resistance means its locking up. Thats when they get noisy.

How do I know if my viscous fan is bad?

To confirm the diagnosis, start with this simple test: Spin the fan as hard as you can on an engine that has not been started that day. If the fan rotates more than five times, you can bet the clutch is bad. You should feel some resistance and the fan may spin up to three times, depending on the ambient temperature.

How do I know if my viscous fan is working?

How do you know if its working properly? When your motor is hot, you should be able to hear the fan kick in. If you can't, pop the bonnet, and turn the vehicle off while watching the fan. If it comes to a fairly abrupt stop, the fan hub is working properly.