AR6500 Diesel Treatment upgrades fuel by boosting cetane levels in your fuel. AR6500 contains high levels of detergents allowing it to clean and maintain the entire fuel system including the DPF and turbo. If your truck has over 50,000 miles or you have noticed a drop in performance we recommend AR6400-D at first fill-up for a deep clean and then AR6500 to maintain and boost your fuel system.