To add to this my work truck , which isn't a 7.3 it's a '23 F250 with the 6.8L but the engine went down in it with 60k miles on it. Lifter failure and lost 3 cylinders had low compression. 5w30 semi synthetic was used every 5-7k usually Napa or motorcraft with a motorcraft filter. It is used off-road , idled a lot , towed with nearly everyday and doesn't get shut off from 5 am till 6 PM most days. Is recommend a good full synthetic in a 10w-30 or 40. If used hard. Otherwise just a full syn. 5-30
