What motor oil do you Cummins Guys and Gals like and don't like. I am going from a PSD to my 97 Cummins in my swap and would like some insight. Thanks

 

In the winter I run Shell Rotella 5w-40 Synthetic.

In the warm months I run Shell Rotella 15w-40

And I change oil every 4,000 miles because I'm **** like that

 

I use 3 gallons of the regular stuff and, always one gallon of full synthetic...of course more if i can[sticks to the engine parts over night]

 

Just being nosy here. Why are you mixing syn with regular oil?
Do you expect any advantages? I don't get the point of those homebrew mixtures.

 

Well some synthetic is better then none. When i can i use full synthetic because it sticks to the engine parts over night and all in all it protects better then regular stuff. If i can afford it i'll do a full synthetic change if not then i'll use at least one gallon

 

Ah, I see.
Interchangeability of oils allow to do this without harm.
But I wouldn't worry about the stickyness to engine parts over night. Even normal oil will cover the interior parts with a thin film of oil.
I've seen a bunch of engines from the inside. The difference of synthetics to standard oil was the cleaniness of the inside.
Engines were synthetics were used were so clean that you eat of them after wiping off. You only will find some stuff in nocks and crannies in engines with standard oils.

 

Today's oils are pretty good all around. As indicated, synthetics can offer some advantages and work well in the cummins. Just depends on how you'd like to run the oil. They do cost more up front but and save money if used as they can be. That's if money is an issue.
If one plans to change oil every 3-5, then maybe there isn't a real need for synthetic unless money isn't an issue and you still want some of the benefits.

 

Thanks, Some good info.

 

Agreed!

 

I like running the Valvoline Blue. I used to run Rotella for years and years and switched about a year and a half ago. I don't know if it's better or worse but one thing I noticed is the Valvoline doesn't stink near as bad as the Rotella.