Probably because I put only 5k miles or less on the truck in a year, and whatever is in the crankcase gets dumped at a year. If the truck were my DD, and especially if it was worked hard I could see the extra $40. expense per change. The Rotella far exceeds the Ford factory recommended 15w-40 oil. For my use, it worksDA BOSS 13,
Why would you pay up to $20.00 a gallon for oil that is "sufficient", having to change it every 7,500 miles.....when you can buy Amsoil DEO 5W-40 or Amsoil DME 15W-40 for $30.00 per gallon, yet only have to change the oil at 3 times the factory recommended interval, or one year, whichever occurs first?
You could save money and have better protection.