Originally Posted by merCrewser
Sorry to throw a wrench into this thread.....
You can run crappy walmart oil and change it every other year and notice no difference.....
I used WalMart oil for a long time in my '90 Silverado and never had a single issue. It's not as if they use 1000 different refineries and have that same number of ways to screw it up. I had also used Valvoline DuraBlend and that worked, too. Eventually, when I guessed that it was approaching 300K, I started using their high mileage oil with no problems. I sold it and still see the guy driving- no smoke or other indication of trouble. I tried WalMart synthetic in my van the last time and it actually runs quieter than Mobil1.