Oil Viscosity should be as recommended in Yanmar Service Manual for outside temperature ranges - SAE 10W-30 will cover you for most of North America for year round use. If the water temperature is above 95 degrees, use 50W oil. The service grade should be SAE CB or CC for moderate duty diesel engine service.
Unfortunately I have not been able to locate a QM15 manual online_.I do know that the GM15 manual suggests 10W-30 I would expect the QM and GM would likely take the same oil.
From most of my diesel experience I have generally found 15W-40 outperforms 10w-30. While on the same theme does anyone know the Fram filter part number ? Once again I am assuming that GM and QM likely take the same filter_
IGNORE the oil filter question....I found the answer in the archives here... it is a Fram PH3593A
