Just a Hypothetical offer between me and the oil god here: "Outrun chooseth you may but one oil and viscosity for you car, and lawn tractor supplieth I will free for 10 years. Commandeth though you must use this oil faithfully and just" Difficult choice is it not? Delvac 1 15W40, 5W40 SUV/Truck or Royal Purple Longrider 15W40? Or an all purpose tried and true 10W30 Redline or Amsoil? Or Belgian Castrol 5W40? You guys be the judge!