Bad fan clutch?

[locovaca]

Working on trying to get my MPGs (2.3, get only low 20's in nearly 75% 65 mph driving). One item that has always haunted me is it seems like it takes a while for my temp to get into "normal"- usually 5-10 minutes of freeway driving it finally makes it up there. I already replaced the thermostat (which was definitely bad, I now have heat), have a new heater core, and flushed the entire colant system.

So my next stop is the fan clutch. I've been reading and it sounds like, if I give the fan on a cold engine a good push, it should go around 2 full revolutions before stopping. My fan has so much resistance that it barely turns two blades. Am I correct in thinking that the clutch is shot?

 

[4x4junkie]

No, a stiff fan clutch when cold is normal.
A bad/worn clutch is usually indicated by noisiness, and/or an apparent reduction in the cooling efficiency of the air conditioner in stop & go traffic, followed by the engine running hotter.

I would look at some of the sensors maybe. I think a bad O2 sensor can affect mileage, as well as bad coolant and airflow temp sensors (also a bad thermostat, but you already got that).

Pull the engine codes. Sometimes a code will be present even though the Check Engine light isn't lit.