Sportage 2000. Needs a new thermostat (I spent last winter with a cardboard in front of radiator).
Naturally...steel bolts into an aluminum casting.....of course they are seized.
So..was able to unscrew the center one, but the front one, even with progressive back and forth motion...just snapped off. Anyway these two can be drilled through and replaced with nut and bolt...because there is room under. BUt the last one, engine side, MUST go bottom access for a nut. is the experience of others on this matter.

....for the time being, I'm going to let the 3rd one alone ...not searching for trouble...and go with the nut and bolt solution for the first two....and reinstall my piece of cardboard....