Synthetic vs Dino Oil ??
Cummins 8.3 ISC Diesel engine. Has about 30,000 miles. Currently has Synthetic oil in it, I assume it's been using synthetic for some time. Need to change the oil. Should I stick with Synthetic or...
Forum Discussion
Cummins gives no extended intervals for synthetic. There are some fuel mileage benefits but I doubt you can cover the cost difference between syn and dino. The synthetic has benefits at the temperature extremes, very cold or very hot. I use Delvac1300 15W40, Delo and Rotella 15W40 are other choices. Pick one. Change it yearly or at 15k miles. Get a used oil anaylis to track trends. Enjoy the trip!
