When I changed the oil in my engines, 2000 7.4L Mercruisers with closed cooling, I took samples of the oil to have analyzed. I have done this on every boat I have owned. This was the first time I have sent them in since I just bought the boat in August. When the reports came back the lab noted that there was a trace of coolant in both engines. I have not had a chance to talk with my marine technician about this but has anyone else had this before? Just curious what I may be looking at. Thanks.