Already time for a cooling system rebuild.

After reading all the sage advice here, I got to work on it a bit after work.

Found the drain tube on the original overflow jug may have been blocked. Dug some stuff out of the top end and blew more debris out with compressed air.

Pressure test found no leaks, and did not even drop.

Oil level and color were fine.

Car started fine, with no steam or water at the tailpipe. Test drive around the block revealed no issues. Can still smell coolant, but that be from Saturday's mess.

Will plan for a flush on my day off (Tuesday).