checking clutch fan

[farmerherb]

What is the easiest/best way to check to see if fan clutch is working. I'm getting a vibration that I can't pinpoint. I changed the balancer pulley(rubber was cracked, Korean made) still feel it.

[Scooby]

You could try removing the belt and running the engine briefly to see if you still have the vibration. Usually a bad bearing in the fan clutch is real obvious as the fluid inside will leak out, and the clutch wont lock up properly. Another check is after driving, and the system has warmed up, and you turn the engine off, the clutch should be stiff after a few minutes as the heat off the radiator will make the clutch engage. If it still spins freely, it is bad. If the fan clutch is more than 5 years old, I usually change them and find the new one locks up better, and my A/C is much colder. I think they may wear inside, or loose some fluid over time.
Hope this helps.