This run of 4500 miles lasted 315 days at an average of 14.3 miles per day, so mostly short trips. At that rate, we're averaging 5217 miles per 12 months. Winter lows got down below 10F several times and below 0F once this past winter.
This entire run, with the exception of two tanks, was run with 91 octane. I noticed that with 91 octane, the oil level no longer rose on the dipstick. Unfortunately, that did not keep the fuel dilution away, though I do believe it helped. Imagine what the fuel % would be if the oil level was noticeably rising.
I chose M1 ESP 5W30 due to its high viscosity and reputation as a "stout" oil, which I figured I needed with this vehicle. I wanted the ending viscosity to be no lower than a thin 30 grade, so success.
I don't believe I've ever seen a TBN this low, regardless of miles on oil. But 4500 miles just seems too low for this oil to be this "spent". Going forward, I'm considering different approaches: either 6 month oil changes (even though each oil change will only have ~2600 miles), or a short 3-4 month winter OCI, with the other 8-9 months being a longer OCI.
They mention silicon. No work was done on the car in these 10 months, so no gasket sealers, etc to consider.
From the VOA, we know this oil only contributes about 5ppm, so I will take a look at the air filter. I have not checked it probably since last oil change, but it only has 10000 miles / 18 months on it.
Their comment on Magnesium can be explained by carryover of the previous oil which had over 700ppm in its formula.
Oxidation, I guess is normal for this oil. I think virgin values are right around 30?
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