Not sludging, but carbon deposits on the hottest areas of the pistons, the crown and ring lands. I thought that same with the 3.6L in my Durango. How could it have any deposits, because I have run synthetics at low to moderate OCIs since new? We saw the amount of carbon the HPL oil removed from the internals. My HPL run started at 111,000 miles, so more than double your miles, but the deposits surely didn't start after 50,000 miles.I would be hard pressed to believe that I have a carbon or sludging issue given the relatively low mileage and frequent OCIs with nothing but synthetic oils since it was new.
https://bobistheoilguy.com/forums/threads/dodge-durango-3-6l-hpl-5w-20-26-015-miles-on-oil.347523/
Edit:
I forgot I posted a picture of the oil filter from our Charger with 60,000 miles after 5,000 miles of running HPL. This engine also ran on synthetics with 5,000-8,000 mile OCIs. HPL removed carbon...
https://bobistheoilguy.com/forums/t...5w-20-21-079-miles-on-oil.344904/post-5863111