I'v been changing my oil in my 2.7t about every 2.5-3k try to do it before 3k. BUT my friend says that doing it that much could mean i have a oil leak, I know these cars use alot of oil so i disagreed with him but the dipstick was at the very minimum at about 2.5k should i be worried about a oil leak at all?! I don't notice bluish smoke out the exhaust but the tailpipes of the muffle are heavily covered with black particles but thats probably normal.