[rdlamb]

Weighing in on this issue may be somewhat dangerous, but here I go again.

Oil is not oil. You need a certain level of protection, lubrication, and specificity for diesel engines.
Using a SF grade oil will void your warranty, you need an oil specific for a diesel engine, then specific for a heavy duty diesel engine,
then specific for your climate, and so on.

Your Cummins dealer or Freightliner, will be glad to help you in these areas.

I've found several oil and air filter choices by visiting my local Freightliner shop. My TM currently has Rotella-T oil and Baldwin air/oil filters.

Also, I use Lucas Heavy Duty Oil Stabilizer. My TM may sit for a few months without being started. Having a cam shaft bearing grabbed during starting
will be expensive. Check out the Lucas site for some details, I am not a dealer nor particular to just Lucas.

Finally, my family runs a trucking company, and does farming. We have enormous diesel engines working all the time. Most have Cenex oil and filters in them, but I'm not afraid to
use Rotella or Delo, or Delco. When traveling, if you need to add oil, I'd be confident the truck stop will have one of these. Additionally, I think the best place to fill up is at a
truck stop. Truck stops cannot afford to sell cheap diesel.
Use the best oil/filter you can, change them on schedule, and worry less.

Last, I do not like a mechanic that recommends the cheapest oil you can find. Oil may be refined at the same factory, and have the same base lubrication properties, but the similarity stops there. The big oil companies use additives and additional refining to produce their individual truck oils. Many put on the product that they are willing to pay for damages caused by their oil. Unless your mechanic is willing to replace your destroyed parts, caused by cheap oil, I'd steer clear of his advice. That coach of your is expensive.