In High School I had a friend who owned a '63 Dart GT that had an semi-automatic oil changer. Old oil would go out the tail pipes and then he would just add new oil in the engine....seemed as if it "changed" it's own oil every couple of weeks...........It was one of those 200,000 mile engines that had never had it's oil changed.....and as the mechanic told him....don't touch it, as you will mess up what ever magic that was keeping it going.....(ran for years until he sold it and the new owner parted it out....as he just wanted the front clip...sad day for my friend when he heard the news)