Ditto on what Tom C posted. I went through the "where's the water going" after operating for seven years. Took the bus to a heavy equipment repair shop. The two possible sources for water getting into the oil are the water pump, and number two, the cylinder sleeve (liner) seals. If I recall there were three individual seals on each liner. The cooling system has to be pressurized to check on either. To check on the sleeve seals the oil pan has to be off. Took an oil sample and sent it off. Came back with minerals in it that only come from evaporated anti-freeze.
In my case I had one sleeve that was leaking slowly. Pulled the head off and found some vertical scouring of one sleeve so pulled the head on the other bank and found two more scoured liners. I had an in chassis rebuild done. That's another story.
The liner kits ran around $500.00 each shipped from California. Total cost was right around $21,000.