Want to run 15w-40 "heavy-duty" oil in a '95 Chevy Lumina with 110,000. Beena around diesels all my life, and realize how good these oils are in relation to the usual oil that fills a cars crankcase. Since all three (Rotella T, Delo 400, Delvac 1300) are "mixed-fleet" oils, I see no problem running them. Should give me better protection, less valve train noise and clean it out a little as well. Anyone here have a recommendation on which I should choose? All seem fairly matched. My only experience is with Delo...Dad ran it in his fleet of semis...good stuff. Thanks, Justin.