These engine burn very clean
I agree with Bill on the dino oil. I ran 6K changes on dino oil. Switched to synthetics at 60K and up the changes to 24K. No bypass, just a new filter every 6K. I have sampled every 6K starting at about 20K. I hotshotted for the first 190K (extreme pulls, over loaded, arctic winter driving). I have never had an oil sample show the oil breaking down, wearing out, or over loaded with contaminents or SOOT. NEVER! Even out to 26K with synthetic.
I have also seen the condition fo the head, cylinder walls, rocker arms after 200K miles and these longer oil drains. I would guess it was as good or cleaner the a 3K oil change truck.
Those of you changing at 3K, why don't you change the tires at 10K. There are relatively cheap. It would be good insurance to prevent a blow out or tire failure. You don't becuase you can see many more miles of useful life yet! The same applies with oil. Grab a sample if you need proof. Todays oils are awsome. Our Cummins engines run extremely clean.
Rather the push synthetics, I think dino oil such as Delo or Rotella changed ever 6K if you drive less then 2K per month should be the more conservative. The 3G oil change is 7. 5K on the severe side and 15K for normal driving. If you run more then 2K per month even towing or heavy hauling I would change the filter (Stratapore LF3894 is one best) ever 5K and oil at 10.
Any engine falure resulting from a leaking injector, antifreeze leak, etc will do its damage in 3K or less miles. This is were a oi sample ever 10K or more would be more benificial the dumping the oil ever 3K.
JMO
jjw
ND