RETAINER 2P3426 - Caterpillar

Ammonia is required to reduce NOx to nitrogen and water. Urea (Diesel Exhaust Fluid) is a nontoxic source of ammonia. The DEF is slightly alkaline with a pH of 9.0 - 9.5. A 32.5 percent solution is used to ensure that the SCR system receives the proper concentration of urea. This concentration is needed for the chemical reactions that reduce emissions.Diesel Exhaust Fluid (DEF) Recommendations
DEF with a concentration of either 32.5% or 40% and meeting "ISO 22241-1" must be used.Caterpillar recommends the use of DEF available through the Cat parts ordering system for use in Cat engines equipped with SCR systems. Refer to Table 1 for part number information:
Table 1
Cat Part Number Container Size
350-8733 2.5 gal bottle
350-8734 1000 L tote In North America, commercial DEF that is API approved and meets all the requirements defined in "ISO 22241-1" may be used in Cat engines that are equipped with SCR systems.Outside of North America, commercial DEF that meets all requirements defined in "ISO 22241-1" may be used in Cat engines that are equipped with SCR systems.The owner/operator should provide documentation to prove that the DEF is compliant with the requirements of "ISO 22241-1".To obtain locations of DEF suppliers, call (888)-598-8186 or (309)-494-7532.
Cat does not warrant the quality or performance of non-Cat fluids.
Do not use agriculture grade urea solutions. Do not use any fluids that do not meet "ISO 22241-1" Requirements in SCR emissions reduction systems. Use of these fluids can result in numerous problems including damage to SCR equipment and a reduction in NOx conversion efficiency.
DEF is a solution of solid urea that is dissolved in demineralized water to produce a final concentration. DEF concentration of 32.5 percent is optimal for use in SCR systems. DEF solution of 32.5 percent urea has the lowest attainable freeze point of −11.5° C (11.3° F).Consult the Troubleshooting Guide and SOTA for test procedures and tools to measure DEF concentrationDEF Guidelines
Quality of DEF can degrade when stored and handled inappropriately or if DEF is not protected from contamination. Details are provided below.Note: Refer to Special Publication , SEBU6251, "Cat Commercial Diesel Engine Fluids Recommendations", Contamination Control section for detailed DEF cleanliness recommendations.If quality issues are suspected or a DEF quality fault is active, testing of DEF should focus on urea concentration, alkalinity as NH3 and Biuret content. DEF that does not pass all these tests should not be used.Caterpillar recommends that customers purchase the pre-mixed DEF urea solution from a reputable supplier. The DEF must satisfy all the specifications of quality. Refer to Special Publication , SEBU6251, "Exhaust Aftertreatment Fluids Specifications". Urea solutions that are not made of urea and water of the appropriate quality and cleanliness may damage the SCR system. Poor or questionable quality DEF can lead to more repair and maintenance costs to the customer. Cat warranties do not cover failures caused by or related to use of out of specification urea solutionsMaterials compatibility
DEF is corrosive. DEF must be stored in tanks and carried in lines made of corrosion resistant