Low Pressure Fuel Supply Hose Leak

On November 27, 2018, Daimler Vans USA, LLC submitted a Defect Information Report (DIR) to NHTSA describing two engine compartment fuel hose connection defects in certain model year (MY) 2016 and 2017 Mercedes-Benz Metris vehicles (Recall 18V-837). The recall scope includes approximately 12,383 Metris vehicles manufactured from March 2, 2015 (SOP) to March 15, 2017. The defects may result in leakage from an upper hose connection that feeds the high-pressure fuel pump or from a lower hose connection of the fuel transition hose between the underbody fuel line and the Shrader valve. The upper connection defect was caused by thermal aging of the hose material (Veritas hose), resulting in a loss of elasticity over time. The thermal aging of the hose leads to a progressive reduction of sealing performance, which is most evident at low ambient temperatures. The problem was corrected by changing to a hose with better material properties (ContiTech hose). The lower connection defect was caused by a manufacturing process problem, where the hose clamp may have been installed using an incorrect tool. The recall remedy involves replacing the upper and lower hoses and clamps, as necessary, and ensuring proper installation. The Office of Defects Investigation (ODI) opened Preliminary Evaluation PE18-002 to investigate nine (9) complaints (VOQs) reporting incidents of gasoline odor or leakage in nine (9) model year (MY) 2016 Mercedes-Benz Metris vans (subject vehicles). Eight (8) of the VOQs indicated that the problem occurred in cold ambient temperatures, either during engine warm-up after a cold start or after the vehicle had been parked and shutoff. Two (2) of the consumers have indicated to ODI that the problems were diagnosed by dealer service technicians as the upper hose connection defect. As part of PE18-002, ODI analyzed information related to the incidents reported to the Office by consumers and analyzed the information provided by Daimler Vans in response to ODI's inform