I was just trying to prevent problems caused by running cleaners like seafoam through in the oil. Marvel Mystery oil is an oil of some type, some say it is auto tranny fluid, although I don't think it is - doesn't smell like it anyways. I put the marvel with Rislone and Wynns friction proofing - been around for 50+ years and still used by many in their vehicles. I do agree that you want to flush the sludge out of a motor to get it to run better, just have to be careful how.