I'm not sure. I think the unit time is Miles on the vehicle and lube is miles on the oil. It's not mine as stated so I'm not here to debate intervals. Just figure out the elevated oxidation levels.First, I don't understand how the lube time vs the unit time figures add up. Second, IMO 30k plus miles is too far to run s S60 on conventional(T4) oil. I would drop to 10k which is where ours are on a somewhat comparable oil and increase 5k miles each time until the sweet spot is found. I think the oil was in use too long.
It was changed at 103k miles after the lab suggested to change it.Soot, oxidation and viscosity going up, TBN getting low.
I don't know the "condemnation levels", but maybe it's time to consider changing the oil.
Our trucking fleet has been doing Fleet tests for Delvac 1 for over 20 years, ever 12,000 miles the truck would be brought in for an oil sample and filter change. We were in many cases running an oil change 100,000 miles or more with zero issues and our engines are Series 60s and Mercedes.If I’m reading that correctly, he hasn’t changed the oil in 120K miles?? I see “lube changed - no” in all samples
Our trucking fleet has been doing Fleet tests for Delvac 1 for over 20 years, ever 12,000 miles the truck would be brought in for an oil sample and filter change. We were in many cases running an oil change 100,000 miles or more with zero issues and our engines are Series 60s and Mercedes.