Recently purchased a '99 F-350 w/ 7.3L diesel, 78K on engine and used 1 quart during first 1100 miles I've owned it (3 weeks mostly highway) using Rotella 10W-30. Any ideas why or things I should be concerned about or have looked at? Thanks

 

Welcome to the site!

You might ask this question in the diesel forum as many of those guys don't seem to frequent this one as much.

 

If you open your fuel filter housing and check the color of the fuel it may give you a clue. Injector O Ring failure will cause motor oil to get in the fuel, giving the fuel in with your filter a dark color rather than the yellowish green clear fuel you should find.

Dave / Believer45