Here are a couple reasons why I would vote for M1:
a) It's better oil by most reckoning; not simply my opinion.
b) Mobil runs BIG rebates often, and it's frequently cheaper. It is right now ($12/5qts rebated).
c) Besides being cheaper, I'm comfortable running a longer OCI with it. So it gets even cheaper by reckoning per mile.
d) Your truck's age argues strongly for an HM oil.
e) You tow.
Quote:
High mileage is only needed if your truck leaks/burns/consumes oil.
I'm not sure where this idea comes from, but it's just not true. The stronger additive package n HM oil does more than "plug leaks." And speaking of leaks, why wait for a leak to start? Why let seals deteriorate to the point you have to hope a cure comes out of a bottle? Keep them healthy before they leak.
Also, in FL, skip the 5w-30 and get the 10w-30 HM. More robust and fewer VIIs to break down. It's ACEA A3/B3 vs just A1/B1 for the 5w. In my mind, there's a lot of reasons to use it and no good one not to.