Re: The mistery slick
I would like to thank all who responded, but in particular Jeffrey Kaus and Bill Kinney and Trevor Lusty: you were in the right track. Failed oil cooler.
However, the transmission oil cooler by www.ejbowman.co.uk came out OK....
... the problem was the Yanmar 100 HP turbo's oil cooler. Had to get a new one for $1606 + VAT (parts only).
To test both oil coolers, they warm them up to 75°C or so and then inject compressed air. Then they look for air bubbles.
For those with oil in the water but no smoke/engine performance issues, check this first.
SM2K Nr. 350 (2002)