ML320 Viscous Fan
 

Hello again,

Now I think the fan is not working properly. As I was watching the engine I notice the fan would not spin, seemed, as fast as the engine. When rev'ing the engine I notice the fan not gong any faster. Questions is, How can I tell if i need a new clutch for the fan?

That clutch doesn't engage until it gets hot enough. Check the clutch when the engine is hot. Your car would overheat pretty quick if the clutch was defective, that would be a good indication. And if you find that it does not engage, first check and make sure you have sufficient coolant flow through your radiator. The heat coming off the radiator is what engages that clutch.

Thx...I will give that one a try...