5K Cooling Questions

[Steve Sherman]

Today my 87 5KTQW overheated.  Turns out a loose connection in the
in-line fuse to the rad fan was loose and the fan was not coming on.
Let things cool and it looked like the res was still 1/2 full so I
continued on after tightening the loose screw.  About 1/4 - 1/2 mile
later I noticed the heat guage going up fairly fast so pulled over
again.  Now the coolant reservoir was empty.

When I finally got back after walking home, I refilled the system with
about 3qt+ of water.  Everything seem to run fine, but I am a bit
concerned about what running 3qt+ low for that short distance might have
done.

Any thoughts, comments?

TIA