The high mileage oils for older cars and trucks were introduced starting a few years ago. Are they mostly just hype? These oils cost about two bucks and change, and regular motor oils cost about a buck and change. The high mileage oils contain seal conditioners and are supposed to reduce or eliminate leaks from seals, and reduce oil consumption. Do they really work or would a person be better off using a regular oil and Auto-RX? Are the high mileage oils just a sales gimmick? Personally myself, I have had great luck with Auto-RX-it seemed to remove sludge from the engine and the slight leaks that I had seem to have completely stopped.