This customer lives in Canada. He has spent a significant amount of money in freight to get our oil in his 383 Stroker. The engine has 200,000 miles on it. The last 180,000 of those miles is on HPL. The oil filter is NAPA gold. I just received the pictures. I have requested the drain frequency and will post that when I get the info from the customer. The engine is in a Boss Hoss and this guy is a riding animal. He will hop on his bike and ride from Eastern Canada to Arizona or Vegas or Florida on a whim. The oil is our 5W40HD CI4plus/SL. This formula has ester but not AN. It is fair to say that the addition of AN in the current 5W40 will help but its hard to imagine an engine running much cleaner than this. The valve cover was removed and set on the bench and photographed untouched.
If someone used an oil that gave very poor engine protection due to much too low viscosity and/or lack of effective AF/AW additives, it could cause wear even if the oil is clean and changed every 1000 miles or less. That's an extreme example, but yes it's possible in an extreme case.
HPL cleaner in a BMW N52 3.0 liter. Not sludged, but typical crusty buildup from BMW dealer service for 125k miles. Crusty, hard, would not wipe off with a paper towel. I wanted to see how effective the cleaner is.
After just 500 miles. No wiping or cleaning except the rubber seal ring. Won't remove the valve cover for you because it isn't leaking.
Can also report the lifter tick totally gone after 100 miles.
That is just on the oil filler cap which only gets random splash oil on it, not a steady stream of lube. No oil splashes out when you pull the cap off when idling. So, it stands to reason the insides that get a flow or sling off from the cams, rockers, chains, crank, etc. will clean up beautifully.