My cousin hit something on the freeway and doinked the cast alum oil pan on his 850 Volvo Turbo. I helped him do the pan change and after looking at the bottom end he did an Auto-Rx treatment to clean it up. He did two cycles at about 150k miles and after the second cycle we removed it again, now that we are experts on oil pans. This time it looked like a brand new engine, exactly like it was assembled that day. The compression did not go up much but now it's dead even in all 5 cylinders, withing a couple of pounds, highest to lowest. It went from a 10psi spread to 3psi spread, plus or minus the gauge accuracy. The underneath was not bad before the treatment but it look dark and you would get black stuff on your fingers. Now it is absolutely clean and you get a clean oil color on your fingers. This is not to say that we don't have better things to do than stick our fingers in a Volvo but the only way to figure out if something works is to try it.