Pennzoil 5W-20 evry 2,000 is what my local police uses. I know several of the officers of that departments. They put 6 hours of their 8 hour times three shifts a day. And of the seven cops six drive those cars everyday drive like sixteen year olds whith there first wheels. We have one with 145,000, two with 80,000 to 100,000, and an 06 with 50,000 to 75,000. not a one of them use a drop between oil changes noe do they show any signs of slowing down anytime soon.