Newby with milkshake in the oil pan 3.0

[Banjo5]

So I air pressure tested the block by plugging the thermostat housing outlet and pressuring the water inlet to 20 psi. It held rock solid. I put 4 fresh quarts in her and took it out in the lake for an hour. Oil is pristine. I really think it was just condensation from the PO not running it long enough to cook off any moisture. A week of worry for nothing. Lesson learned.