If you have an unmodded blue hub then that's probably 100% of your problem. Mine's been modded 3 times now. First with 10K fluid, then 15k (or 20k?), and now with 30k.Everything you just described is what happened with mine last week.
I just went out and checked and the new fan clutch I installed is an Aisin, blue hub (I have not modified it) and I have a new fan on there. I am going to swap out my hub and change the oil in the blue hub and modify it per Landtanks' notes to see what I get.
When I spin the fan by hand on a cold engine, I get about 1/4 turn before it stops.
I have NEVER had an issue for cooling prior to this, so I am very concerned. Nothing has changed on my engine to bring this on, other than finding the old T-Stat only half open. I cannot imagine what the folks in AZ deal with on a regular basis.
I guess my thermostat could also been only half-opening, since you're not the first to report that either... new t-stat is ordered, probably arrives early next week.