1995 G-20: Thermostat Stuck?

[Shrewz92]

Vehicle is 95 G-20 Conversion van with 5.7 engine, automatic trans, wide tires all around.

Had serpentine belt come off all pullies due to broken Alternator bracket. Drove vehicle 9 miles back to house with no Power Steering, no water pump (water temp showing approx 180, the mid-point mark on my temp guage, and coolant high in overflow container when checked at home/destination, noticed small coolant amount around top of radiator cap center valve at destination immediately after reaching destination, with engine off), no alternator (guage read 10v). Replaced bracket and remounted same belt, which showed no damage. Alternator showed charging at 14-15Amps. Was late night when job finished, so no long drive to test. No idiot lights, so I assumed job was done, correctly.

I noticed on next day's trip to work that water temp guage slowly went to 140, which is where it had been reading prior to break of bracket. "Slowly" defined here as "prior to break, reached 140 degrees within 3 miles @ 40mph, now taking almost my full trip to work of 13 miles at speeds of 55 mph+ to reach 140 degrees." Today, it rested between the 100 & 140 mark, maybe 120 - 130 degrees. Coolant is up in the neck of the radiator and at 'cool' level-mark in overflow container.

Would the 180 degree temp damage the thermostat, keeping it held open? Would the old shade-tree mechanic's cure of tapping the thermostat housing release the spring to closed position?

Also, since replacement, noticed rhythmical 'clacking' coming from area of power steering pump (which has a slow leak, also). Would forcing those wide tires around curves and sharp turns have damaged the non-working pump?

[MT-2500]

I would put a new AC Delco 195 degree stat in it and see what it does.