Well, here’s the latest. It’s by far the worst change from month to month, as you can see.
Since August I’ve been going deeper into the revs… 6k RPM to 7k RPM, now that the 1.8 is broken in*. If that doesn’t explain the suddenly darker-than-expected engine oil color than I’m at a loss.
I’m going to look at the air filter. See if that offers any clues to the dark oil. Engine oil should not be this dark after 6 months and 5200 miles.
I don’t run the car in dirty conditions, off road, inside coal plants’ smokestacks, etc. I always run 91 octane, every time. Running premium fuel is one of the Three Things I Always Do for my Alltrack.
*There’s no power up there, at least no more than say 5k RPM offers. It’s flat from 5k-7.5k RPM.