Magnum 5.9L-- which motor oil/weight?

I use a PH16 filter and Valvoline 10w30 "high mileage" because it is a syn blend, and reasonably priced.

Just like LA engines the valves will tell you if it's a quart low, or if it's time to change- should you be otherwise unaware.

My 2000 Dakota R/T is about to cross the 150,000 line in a few months.

I've run the Rotella T in my 73 Satellite 318.

Not necessary for the Magnum unless you are putting in a non-roller cam.