Actually, you were partly correct. It should be stiff when cold - otherwise, the fluid has leaked out. When cold, you shouldn't be able to spin it.

But as the fluid warms up, the fan will spin a little easier until the coil locks the clutch.... which allows a gradual engagement depending on temperature. If the coil goes bad, the fan will spin when hot even when it's full of fluid.

Frank

'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum