yup, only a rope seal will sometimes stop leaking on it's own, my '51 chevy did that, rear main rope seal used to leak when I first got it, but after it got wet with oil, it stopped leaking. some stop leaks will clog up oil passages, as they actully turn into a sludge purposly. don't put brake fluid in the oil ither, it does more harm to good seals, than it does good to the leaky seal