Car parked overnight on slightly sloped driveway (nose up). This morning, small coolant puddle under water pump area, with slow drip continuing.
Reservoir looked empty, and check under radiator cap showed full. But slow drip seemed to pick up speed. I quickly put cap back on and put a pan under the drip. Had to do other things for a few hours.
Came back to car and pan only had maybe 6 ounces of coolant in it. Started it up and moved it into garage (level surface).
The leak stopped!
Reservoir is definitely empty, and I haven’t opened the radiator cap again in case it vents and lets coolant stream out (although reservoir leaves an air path to do that as well).
Poked around the water pump (OEM after about 175k) and it looks like it is the leak, although I cannot completely rule out connection with lower hose, which is right under the pump.
What happened to stop the leak?