This week, the National Highway Traffic Safety Administration (NHTSA) acknowledged a safety recall from IMPCO Automotive related to Chevrolet Express and GMC Savana cargo vans equipped with compressed natural gas (CNG) fuel systems.
IMPCO submitted a recall notification to NHTSA in mid-May, which is required under the agency's defect reporting regulations. The issue involves the solenoid that opens and closes the flow of CNG in these vehicles when the engine is running/turned off. Italy-based OMB Saleri SpA was the supplier of these solenoids.
The nature of the defect is reportedly that the solenoids could corrode, and a short could form in the solenoid connector. If the device shorts, overheating is possible, and by extension, a ‘self-extinguishing flame’ could occur. If that scenario played out in the presence of a CNG leak, ignition of the gas would be possible.
IMPCO reported that four shutoff solenoids are integrated into each vehicle's underbody CNG system, at the CNG tanks and the high-pressure regulator.
According to IMPCO, the recall notice affects CNG fuel systems manufactured between February 2011 and February of this year – all of which were supplied only to General motors and are found only in dedicated CNG Express and Savana vans. A total of about 1,800 vehicles are affected.
The problem was first reported in February, when a GM customer in Massachusetts ‘observed a flame under a vehicle equipped with the subject fuel system.’ Representatives from IMPCO, GM and OMB Saleri checked into the incident and confirmed that a solenoid had melted.
Two vehicles in a Vermont-based customer's fleet were also confirmed to have partially melted solenoid connectors, and one vehicle in Wisconsin had two faulty devices.
IMPCO thereafter performed lab tests to replicate the short and identify the root cause, as well as examined 13 vans at random. None of these vehicles was observed to have faulty equipment.
Based on its investigations and tests, IMPCO started the recall process in early May. The company plans on working with GM to notify dealerships and vehicle owners about the defect. At that point, IMPCO and GM will coordinate the replacement of all solenoid assemblies and fuel pump fuses, as well as the adjustment of certain wiring routing.