Yes, but Pennzoil specifically says it's oils will clean existing sludge.
Marketing. PYB is a good product though don't get me wrong.
All oils have cleaning agents and when used as intended, will keep your engine at least (fairly) clean inside.
Its Synthetic-ness and Detergents package probably attack the Sludge pretty hard, or whatever the Oil thinks is Sludge. Then it likely holds it in Suspension until changed.
I would think that the oil would darken rather quickly if it is as agressive as Pennzoil says. Others have expressed skepticism.
If i can find 15W-50 for my application, im going with Pennzoil. I will search for it before i give up, them M1 will be used if i cant find PP no need for PU. It is simply a matter of whatever is there, and whatever works. Both these Oils will likely suit the bill, though i will seek PP before using M1 with no worries and no qualms. Ive done my homework. And i do NOT think it will "Eat up my camshaft."
The only thing i would be concerned about is Leaks. If PP is so smart it can remove Sludge that well, then MMO is not needed, that seems a product for non-Superstar Sludge Cleaning Oils in which case it works well, though some frown at solvent in crankcase. I can partially see why, as Oil does that function already, so why not add MMO.. n/m.
I say again, if PP can clean sludge and not make Leaks appear by claning away sealer sludge, Ihave found an Oil for Life.
Has anyone ever had leaks arise after using PP? Or has it acted as a good Sealer and Seal Conditioner with its additive pack, while working its de-sludge magic? They seem Opposites.
but as to the "PYB Sludge Horror," I have come to the conclusion that.. While a handful of people have no reason to lie and probably were mechanics and probably tore apart engines in the 70s and 80s (likely in engines of the time that were unknown sludgers back then) in which case it would have had a bad rep into the 90s until new PYB came along, I believe that calling new "Exceeds API SM" PYB Sludgers is very
insulting, based on all i have read here. And i dont even use PYB. JMO, and its far worse than ANY Attack or Comparison or Test against other Oils on M1 ive seen, which i may end up using in my application.
PYB Sludge sayers, if speaking in Modern Day and not about decades past gone, are