Diesel exhaust fluid is one of the key elements of the Selective Catalytic Reduction (SCR) process used by most medium and heavy-duty engine builders to meet EPA 2010 regulations. BlueDEF is a nontoxic solution of 67.5% purified water and 32.5% ultra pure automotive grade urea. It is not a fuel or fuel additive. Instead, when injected into the exhaust stream and passed over a catalyst, this solution helps convert NOx into nitrogen gas and water vapor—two harmless and natural components of the air we breathe.
DEF begins freezing at 12° Fahrenheit (-11° Celsius). If it freezes, the engine will still start and run properly (no de-rate or malfunctioning lights). The tank heater will thaw the fluid for use and at no point will this affect the operation of the engine. The engine will also continue to run even if you run out of BlueDEF. However, if the tank is empty, engine horsepower will de-rate and you should add more BlueDEF to the tank.
DEF is stored in a dedicated tank next to the fuel tank on the driver's side. The tanks range in size from 6 to 23 gallons depending on the truck's application. The DEF tank fill opening is designed to accommodate a DEF fill nozzle to ensure only DEF is put into the tank. A diesel fuel nozzle will not fit into the DEF tank opening.
BlueDEF is stable, colorless and odorless, and meets ISO Standards 22241 for purity and composition and is an American Petroleum Institute (API) certified diesel exhaust fluid. These are the highest quality and safety standards in place to ensure optimum SCR performance.