Originally Posted By: steveh
I think I can believe this if its all highway miles. If you divide 20,000 by 60mph you have 333.33 hours. I do almost all city miles and my trip computer reads about 200 hours in 3,000 miles.
I like this thinking. And you can probably assume that 200 hours of city driving is much harder on the engine than 333 hours of interstate driving.
Back when I had a car that had an AVG SPEED indicator (my old Cadillac), I'd average about 25 MPH on my commute. For a standard OCI of, say, 7,500 miles, that's 300 (hard) hours. 300 (easy) hours at an average speed of 55 MPH is 16,500 miles, so it's definitely in the ballpark.
On the other hand, this was an xB, so highway RPM was probably well north of 3,000 RPM. Oil temperatures may have been rather elevated compared with idling around town. But still...I agree with you that it's certainly not out of the realm of the equivalency of what other marginally-maintained engines get for maintenance.