I had about 370,000 miles on my truck when I started using the ARX back in...August maybe. I got about 385,000 now. I went through two cleaning and two rinse cycles and now I'm just doing a "normal" oil change. I have noticed less smoke at start-up, especially during the summer months but it still uses more oil than I would like. I even fixed a few oil leaks while running the ARX but still uses about the same. With the high miles I have, would it be worth going through more cycles? Even though it's a diesel, it's a very clean engine, on the short change intervals, the oil would hardly get dark at all.