This is the first year that I am filling the case to the brim. Thought four quarts would be enough. Then went back and bought two more. Still not to the top. Where is all this oil going. The duc gets synthetic. This is getting expensive. Not that I would think to skimp here but every year prior to this I just left the old oil in and changed after the long slumber. Is the fresh oil pre winter to the brim all that important? I'm just suprised the case holds so much. :scratch