I think this is just condensation in the crank case. Very common in engines without Pos Crankcase Ventilation PCV. If you are not getting the engine warm ie short trip driving it is worse. Only solution is longer trips, cardboard on radiator, more frequent oil change.
Instead of doing hunt n peck as far as leakage in engine
1. Compression test
2. Pressurize coolant system - if hold pressure for 15 minute no problem. Do NOT go over say 10 maybe 15 psi.
Dan Bentler
