So I am wanting to run the high-zinc oils (Non-Enegry conserving) in my 01 silverado 5.3.
Trouble is, I can only find synthetic 10W-30 (Mobil1 High Mileage) that still has the Zinc wear compounds.
What kind of MPG hit will I take if I go to 10W-30? Have any of you done this? Or does anyone know of a good synthetic 5W-20 that is NOT energy COnserving?
