Originally Posted by aklim

Another thing you can do is to do what I did for my truck. 3000 mile oil change but I am using synthetic and stretching it to 5000 (I have 2 HPOPs which supposedly is hard on the oil and causes shearing of the molecules). How I arrived at this number? Take a used oil sample and they will tell you how "worn out" it is. Blackstone Laboratories is a good one. They will tell you how wore out it is and how far you can stretch the interval.