Lol
I see that OP posted a couple of videos of fan clutches, a fan clutch is never checked by human hand, and if someone is spinning it by hand and claiming
“Iss ko chakarr do to “2 chakkar aur kkatey ga” is out of his mind.
Fan clutches spinning freely by hand are dry and dead, in rest state they would have a lot of drag as the oil inside the clutch has dropped to the bottom and makes it “lopey” aka draggy. (Thats why you hear a clutched fan roar to life for abt half minute to 2 minutes on a first start stone cold engine)
If your human hand can spin it at about 2000 rpm for about 20 seconds minimum (must be a superhuman) then it can tested, otherwise these are tested on the engine itself or on a motor assembly to spin it up.
Seems like your naive approach bit you, a cold freewheeling fan is a bad fan and will overheat the engine as it has no oil to apply drive to the fan blade wheel when the bimetal expands out.
This isnt rocket science but the folks in the video are busy conning the customer.
Source : bimetal spring valve hydrostatic fan clutches work on a universal principle of moving the silicone oil from the reservoir chamber to the drive area and back to the reservoir as the bimetal contracts again. They have been in use for more than 65 years.
Your mitsi one is not rebuildable, a new one is required. And by new I mean brand new.