don't understand concept of radiator fan clutch
 

Hello, I have a 92' Ford Ranger with 2.9 V6. I had my fan clutch replaced today. I don't understand the concept of how the viscous fan clutch works in my make and model. I am referring to the clutch located in the center of the plastic radiator fan

I was under the impression that the fan is stationary and does not spin at all when the running engine is cold. Am I understanding correctly that the fan is always spinning at a slow or fast speed while the engine is running? Is the fan ever not spinning at all and still while the engine is running?

All I see is the fan spinning when I pop the hood with the engine idling in park. I could not hear any sound of the clutch engaging as described by the mechanic while driving.

How can I tell if my fan clutch is functioning properly? And what are the temperature settings for the fan clutch cycles? Can someone explain this in greater detail to me?

Thanks,
Dave

RE: don't understand concept of radiator fan clutch
 

I probably shouldn't reply, 'cause I don't know either...But I think temp isn't a factor, but speed. At high engine RPM's it's assumed you are driving fast which eliminates the need for a fan due to airflow through the grill. At low RPM's the fan is engaged to ensure adequate airflow over the radiator... but at high RPM's the fan is basically idling. The purpose, I'd guess, is that at high speed, there's one less thing for the engine to rotate. Anyone know for sure?

RE: don't understand concept of radiator fan clutch
 

The coil in the front of your clutch is there to detect thermal changes in you airflow thru radiator core. As this detects hotter air it engages the clutch tighter making your fan pull more air, when it cools it will not put the same drag on engine, and free up some power. The fan will never b stationary. Sometimes it will sound really loud when you first start on cold morning, but will then go away shortly and likely you will never hear it again.