The CD-4 (or above) rating the PowerStroke requires is specifically for soot suspension. Since Mobil-1 does not have this, its not a acceptable for this engine.Yes, normal for all diesels I've touched. The best for how long before the oil became black was the Mazda diesel in my 85' Escort because it had 2 oil filters - primary and by-pass.
Yes oil changes are critical..
...BTW your Bieber avatar is awesome.-Malone
Yup my Dodge is a gasser. The 3000 mile interval for a oil and filter change is probably critical for diesels. Is the same true if you run a synthetic oil?
This is interesting reading for us on this side of the pond, as 5000 miles for oil and filter are what is in the book for the old IDI engines, is the difference due to engineering or marketing? :?