HDEO's are the way to go. Rotella T6 rejuvinated my leaky seals and has been slowly cleaning my engine for 8 or 9 years. I actually used quite a few oils before, and during, such as GTX 10W-30 and 10W-40, M1 0W-40, and GC 0W-30.
From my experience, Rotella T6 got black faster than any of the others, leading me to believe it cleaned the best out of those.
From my experience, Rotella T6 got black faster than any of the others, leading me to believe it cleaned the best out of those.