I changed the oil in my wife's X5 and my 545 tonight. Did hers, and when I was sucking the oil out of mine I looked for the filter and couldn't find it. It was cold and wet out and once I figured out that my filter was on the bottom, it was too late to scrub the mission. I refilled my car with new oil but would like to know if I can change the filter tomorrow without losing all the new oil. Is there a check valve that will allow me to remove it without draining the pan? Thanks.