For synthetic oil, I usually change it in my Cummins engine every 7,500 miles or annually. The truck isn’t a daily driver, so for me it’s usually annual.
, 10,000-mile oil changes are for somebody that wants their vehicle to last only 100,000 miles. Not worth the gamble.
When I bought my first diesel in 2002 (F350 Super Duty 7.3L) I remember the owner's manual stating that the oil change interval was 3,000 miles. Even living in Hawaii at the time, that would mean three oil changes a year! I used to buy regular dino oil, then switched to synthetic, added a bypass oil filtration system which would filter down to something like 1 micron, and played the game of sending oil out for analysis to see how long I could stretch the oil change intervals.
It used to be that the cost of refining the used oil became prohibitively expensive, and there was more money in new oil vs refining used oil. Safety-Kleen perfected the market and they get paid to take the used oil, and then they resell it. Safety-Kleen collects used oil from thousands of locations across the United States, Canada, and Puerto Rico. I used to purchase their re-refined engine and transmission oils, I remember it had an eagle on the label, but what it was called has left my memory. Safety Kleen still sells re-refined oils under their Kleen+ label. https://www.safety-kleen.com/kleenplus Follow this Google link to read more about re-refined oils. https://www.google.com/search?q=wha...xNzk3ajBqMTWoAgiwAgE&sourceid=chrome&ie=UTF-8
Just pay attention to the viscosity at high temps when you get it tested. The mighty 7.3 uses HEUI injectors.
