I had a friend that's a diesel mechanic came out last week and look at my Yanmar 2gm. We determined that it needed a pan gasket, a new oil line to the head, a new set of gaskets for the injectors, an impeller kit, new hoses, and a few crush washers.
We cleaned the engine with brake cleaner, let the engine run for about 20 min and found all the leaks like Benny said. We also found that a bolt for the exhaust elbow was missing a head. We determined that with the engine starting to show some signs of rust, it was best to pull it and do all the work on a bench. We're going to clean it and repaint it Everything we need along with 2 cans of Yanmar paint will run about $150 and my engine will be clean and new again. It starts and runs really good, it is just at the point that it needs a little TLC.