Cummins ISX engine oil?

[Toddmsc]

I've always used delo 15-40 or Mobil in all of my trucks. Never any issues or premature failure.

Like he said ^ dont over think it. Pick something that is common around truck stops and is easy to get your hands at for a reasonable price per oil change.

When you settle on new oil, do oil samples for the first 5 or so changes. Run 10k miles then 12k, then 15k. Always look at carbon levels and viscosity of your reports. This will give you a general idea on how far you can go with out wasting oil or going to far and destroying things.

Cheers and good luck