Drove my old '89 Probe down to my sister's ( about 100 miles ) last Friday.
About halfway there, the announcement "Coolant Low" popped up, so I ignored it.
BIG MISTAKE.
When I was but 5 miles from her place, the CEL came on and the temp display pegged at the top.
I found a handy station and poured water in using a paper cup I found in the trash, finally got her cooled down,
but noticed while I was pouring the water in that the 90 degree plastic neck of the radiator cap ( this is a Mazda, after all ) had been chewed by one of the squirrels that Squirrel Crusher had inadvertently missed.
Long story short, got to my sisters and used her car to go find some JB-Weld.
Now good as new, checked it when I got back home, NO coolant loss.