Great stuff! I haven't done a UOA, but I ran it in a sludger for two OCIs, and hapened to have the valve cover off for various reasons before those two OCIs and after those two OCIs. It was clearly visible that Delo 5w40 really did do some cleaning. I had pictures, but changed phones since then and lost pictures in the process. It was not a night and day kind of difference, but more like twilight vs moonless night. Just for comparison - Rotella T6 0w40 did not provide this engine with the same results. Delo 5w40 is great oil - use it with confidence. Could be placebo, but it did made the valvetrain chatter disappear slightly compared to most 5w30. Just my experience with it. Definitely would (and will) use it again.