This service bulletin provides essential information regarding the DEF Return Line Fitting Heater, specifically tailored for 6-gallon tanks. The bulletin covers various Freightliner truck models, including the FLA COE, FLB COE, FLD Conventional, Business Class, FLC 112 Conventional, Century Class Conventional, Argosy COE, Cargo, Columbia (including the 122SD and Coronado), Business Class M2, Cascadia, and 108SD/114SD. The service bulletin outlines the specific procedures and guidelines for addressing issues related to the DEF Return Line Fitting Heater, ensuring proper operation and maintenance of this critical component in your truck.

The DEF Return Line Fitting Heater sb4935 is a crucial component designed to address a specific issue encountered in certain Freightliner trucks equipped with 6-gallon DEF (Diesel Exhaust Fluid) tanks. This heater is specifically engineered to prevent the DEF fluid from freezing in colder climates, ensuring the optimal functioning of the Selective Catalytic Reduction (SCR) system. The SCR system, a critical part of modern diesel engines, relies on DEF to reduce harmful nitrogen oxide emissions. However, DEF, primarily composed of urea, can freeze at temperatures below 12°F (-11°C), hindering its flow and disrupting the SCR system's operation. The DEF Return Line Fitting Heater sb4935 serves as a preventative measure against DEF freezing. Installed in the DEF return line, this heater provides localized heating, ensuring that the DEF fluid remains above freezing point even in harsh winter conditions. This innovative solution effectively safeguards the DEF system, preventing disruptions in the SCR system's functionality and maintaining optimal engine performance. By ensuring the smooth flow of DEF, the heater contributes to environmental sustainability by minimizing harmful emissions. Its application across a wide range of Freightliner truck models, including the COE (Cab Over Engine) and Conventional variants, underscores its importance in ensuring reliable and efficient truck operation in various climates.