All I have to go by is the dipstick tube, because I don't know the capacity of the engine. My guess is that its 6.5L (15w40) in there, maybe a bit more. Its right in the mid range of the dipstick when the engine is warm. When I get the chance, I will pop the valve cover off again and see if there is a plug in the drain gallerys, might also try draining 0.5L of oil out of the sump and see what happens.