I first started using AR6500 after my son and I rebuilt a Ford 350 6.0. My son had ran across the feedback for the AR6500 and because of the great reviews, we wanted to give it a shot. The results in our 6.0 were FANTASTIC. You could hear the difference in the engine immediately. There was no delay. Having to check the egr regularly, we began seeing next to no build up on the egr. The engine sounded better, accelerated better. You could feel the difference when you drove it compared to before its use. Great product. I make sure I have enough for every oil change, every tank of diesel and every 3-5000 miles. We really use our 6.0 hauling, working, and towing. I can't say enough good about it. Shoot we have even added the fuel addictive to our riding lawn mowers and push mowers, which are gas, and they all run waaay better. If you haven't tried this product for your diesel, you have to buy you some. It might seem costly but the improvement on the engine is dramatic which will give you many many more miles out of your vehicle.