Well I decided to use some Castrol High Mileage brand oil in my 88 Lincoln Town Car- this is my 5.0 L ! - winter beater. This car consumes a lot of oil, it also leaks a bit of oil (but not as much as it consumes), and historically the oil turns black very quickly after being changed. After putting in some Castrol High Mileage oil the leakage has either stopped or has been reduced to a very small amount. Oil consumption has decreased very noticeably, and the oil is staying much cleaner as well. I'm pretty impressed so far, it is actually working as advertised from what I can tell. My motor has over 100,000 miles on it. The car seems to run smoother too, but that is a subjective thing. The oil vis is 10w-30. Funny thing the label reads that the oil is comprised of foreign and domestic components - wonder what they mean by that ?. Just some info to share.