I dug around for quite awhile. There doesn't seem to be a fixed temperature of the fan clutch listed in the FSM nor anywhere else.
The general consensus of about 170 degrees f. About 180 to 190f engine temperature. Supposedly cool the engine 20 degrees. That's just general generic information though.
I personally, never seen one leak or have issues. I seen lots of forum folks say they notice when it's not working optimally.
There are some videos out there to rebuild them basically just refill with silicone oil again.
Mine all have resistance and hard to turn when cold engine. Then they spin for a while then disengage after a few minutes of the engine running. You actually hear the air volume from the fan slow down when it disengages.
If they do that I call them good..
Sent from my SM-A505U using Tapatalk
__________________
7 3rd gens listed in the build thread (2 are parts mobiles)
Build Thread:
https://www.toyota-4runner.org/3rd-g...os-builds.html
Brillo's Bucket Fluid Ex changer:
https://www.toyota-4runner.org/3rd-g...ml#post3358086
Sparks Plugs Wire and Coil Information:
https://www.toyota-4runner.org/3rd-g...on-5vz-fe.html