DEF shelf life is determined by how long the solution effectively neutralizes harmful diesel fuel emissions. Typically, DEF expiration dates are set at one year from the date of manufacture. The shelf life of DEF comes from its makeup. DEF is simply water and urea, with a 32.5% urea. . It's simplest and safest to store DEF in approved jugs, drums, totes, or in a designated DEF tank. While cold temperatures, and even. . Given all the elements involved in maintaining clean DEF, many fleets create set handling standards specific to DEF. You may also want to designate an individual to manage expired DEF disposal and help maintain emissions certification and the integrity of the diesel engine components. . Like many fuels, additives, oils, and other liquid components of diesel engines, DEF is only safe and effective to use for a finite period. DEF expires after about one year, assuming it isn't. . Fortunately, it's generally simple to identify bad DEF fluid. Because of its molecular composition, DEF reacts with other liquids and becomes discolored or cloudy. This may also occur if DEF begins.
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