NHTSA Preliminary Evaluation PE25003

The Office of Defects Investigation (ODI) received a complaint alleging a compressed natural gas (CNG) fuel leak from a Luxfer Type 4 CNG 60 diesel gallon equivalent (DGE) 26x108 size fuel container.  The container was used in a system built and installed by Natural Gas Fuel Systems, LLC, dba Cummins Clean Fuel Technologies (CCFT).  A strong odor alerted the driver of the fuel leak, which occurred at a fracture at the fuel container's threaded aluminum alloy fixed end boss. The fuel container is positioned longitudinally within an enclosure structure that is attached to the truck's passenger side frame rail in a side-mount configuration. The fuel container is held in position relative to the enclosure structure via neck mounting blocks and two aluminum alloy end bosses, each at opposite ends of the fuel container. The threaded fixed end boss is securely held in position, while the other floating end boss has some degree of freedom to allow for normal expansion and contraction with internal pressure and temperature changes. The complainant reports they are aware of five other trucks purchased by other customers from the same dealership that have experienced the same alleged condition. Furthermore, previous discussions with CCFT have revealed that they are also aware of other similar incidents. A fuel leak in the presence of an ignition source may result in a fire or explosion. To better understand the frequency, severity and scope of the allegedcondition, a Preliminary Evaluation (PE) is being opened. To review the ODI report number cited in the Opening Resume ODI Report Identification Numbers document, go to NHTSA.gov.