This concerns our diesel 2010 X5...about 5 weeks ago the exclamation point in a triangle warning light comes on, xehicle status says oil at minimum, add a quart. This never happened before. I add a quart. Happily drive for 5 or so weeks and here the warning comes up again while driving. When start up for the next trip, no warning light. After driving a while, it's on again. I don't know whether to add oil again or not. Of course this brings up the question, why the "(add your own expletive)" would you build a car without a dipstick?? Help anyone?