I SWITCHED TO MOBIL 1 0 40 ABOUT 3000 MILES AGO . I REALLY LIKE THE IMPROVEMENT in the coldweather starting . it dropped it 15degrees. the car started at - 36f 2 weeks ago. that was with the block heater and the oil heater on . but the bad is the car has used 3 qts of oil in that time which is not normal with regular rotella oh yea it an 83 300tdt with 248k miles. just my experience.
i am going to 15- 50 at 5000 miles to see if that stops the oil use.
JOHN M