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.
Dodge Durango 3.6L - HPL CJ-4 5w-20 - 26,015 miles on oil
Previous UOA: https://bobistheoilguy.com/forums/threads/dodge-durango-3-6l-hpl-5w-20-21-079-miles-on-oil.344904/ This is a sample pulled from my Durango 3.6L with 137,615 miles total and 26,015 miles on the oil. Consumption was zero during this entire 26,000 mile run, which is a change from...
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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...
Dodge Durango 3.6L - HPL 5w-20 - 21,079 Miles on oil
I'll add that @wwillson you might recall I had a similar experience (but without the trend of UOA's) with my Expedition. It had spent its life on bulk dealer oil prior to our purchase of it and when I started running Mobil 1 in it, I was getting all this carbonaceous material in my filters as...
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