Started hotshotting oilfield equipement with my F150 a few weeks ago, 271k miles, currently have Castrol Edge EP 5W30 in the sump with 2.5k miles on it, Ill run it to 6-7 k and then start using HPL for extended intervals with UOAs. My question is, which HPL to order? 5W30? 5W40? My driving is...