Universal M12 Engine

[bushrat]

My new to me Mirage has the diesel M 12 Universal engine. I just did some maintenance as the boat had been out of the water for the last two years. First off I changed the oil. I used Synthetic oil before I looked for some opinions on the subject. Some posts mention oil leaks with older motors. Is this common. I use synthetic in my vehicles and all my other equipment. I especially like the excellent cold starts you get. My V-Dub diesel car always runs and starts good in our cold winters. The marketing worked on me as well regarding thermal breakdown when they put the oil in a fry pan. The conventional oil turns to sludge while the synthetic stands up to the heat. This is the first marine diesel I've run, should I go back to the conventional oil?