I know that Napa oil is actually valvoline oil. Can someone tell me though whether Valvoline Premium Blue 15w40 is the same oil as Napa brand 15w40? I just bought a Cummins 24v and I know Cummins recommends the Valvoline Premium Blue in there motors. How often do you guys change your oil if you are using a good dyno oil and a good filter like the Wix (Napa) filter? 3K? 5K? ...? Harley
Changing your oil at 3K is for a gas engine. You can run 7-10K on a change depending on a few factors. How much short driving trips you are doing, lots are hard on the oil comapred to freeway miles that are easy on oil If you are towing And how much power the engine is making. Modified engines can be a little harder on oil from the increased heat and load. I am not sure on the Napa brand diesel 15/40, but it's probably plenty fine. If you are interested in a real good synthetic I can get you Amsoil delivered to your door for a decent price, filter and all. You could then go at least 15K on an oil change and have the added protection of synthetic.
