I just bought a used 2002 Chevy S10 with 25000 miles on it. The oil had been changed every 3000 miles with a Dino oil[Pennzoil]. I will drive it to work every day[42 miles] round trip . Should I stay with the dino oil[I change oil myself] or switch to Mobile 1? I will keep this truck for many years as I am retiring in two more years so this vehicle should last me for the next eight years. Truck engine is a four cylinder five speed.