Let me run this by you guys then. I don't plan on driving my car during the winter at all, so what if I left the old oil in there. Its roughly going to be 7,800K and then change the oil in the spring and then put in my "extended life" Mobil 1 15w50? I never had a problem running heavier oil in the past, but with all this tolerance talk, its got me thinking a little bit.