Red Line’s Diesel Fuel Catalyst is designed to prolong fuel system life and improve fuel combustion. Powerful thermally stable detergents clean fuel injectors and the compression ring area that can become filled with partially burned combustion products. A cetane booster is incorporated to reduce knocking and smoke and improve cold-weather starting. Lubricity additives lubricate fuel pumps and injectors while leaving a coating in the upper cylinder, helping to reduce friction at a critical point where the rings change direction. Red Line Synthetic Oil: (800) 624-7958, Online Information.