Join Date: Apr 2017
Location: West Central Sask.
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Stick with 15w40 conventional. It will work absolutely fine in your climate. It's cheap as well.
Synthetic is great but conventional has come so far, base oil is a non issue.
I think it was valvoline that did some wear testing. The lower the spread between the W and viscosity at 100C the better wear protection. 15w40 does better than 5w40, which is better than 0w40.
Obviously cold climate dictates your W.
Viscosity is another story. 30 weights are fine, as are 40 weights. Cummins even states this.
Run a 15w40, 5w40 or even a 10w30. If its CES20081/86 it's fine. No one will care, not even your engine.
2017 Ram 3500 Megacab, SLT, True Blue, SRW, CTD, AS69RC. Ubique