2012 Chevrolet Express 4500

TL* THE CONTACT OWNS A 2012 CHEVROLET EXPRESS 4500. IN COLD WEATHER, THE DIESEL EXHAUST FLUID (DEF) FROZE, WHICH CAUSED THE VEHICLE TO DECELERATE UNTIL IT EVENTUALLY IDLED. THE DEALER (KUPPER CHEVROLET, 1500 2ND ST NE, MANDON, ND 58554) STATED THAT THEY NEEDED TO KEEP THE VEHICLE IN A HEATED SHOP TO PREVENT THE DEF FROM FREEZING. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS ALSO CONTACTED AND WAS UNABLE TO PROVIDE ASSISTANCE. THE APPROXIMATE FAILURE MILEAGE WAS 86,000. THE VIN WAS UNAVAILABLE.

ON 9/30/2016, A THERMAL EVENT OCCURRED WHILE THE BUS WAS IN THE SHOP FOR ROUTINE MAINTENANCE. AS THE BUS WAS BEING MOVED (BACKED-OUT) OF THE SERVICE BAY AND SMOKE WAS SEEN ESCAPING FROM THE CNG TANK STORAGE COMPARTMENT AT THE REAR OF THE BUS. LOCATION: 4127 ELM ST., DALLAS, TX 75226 A DALLAS AREA RAPID TRANSIT (DART) EMPLOYEE QUICKLY OPENED THE COMPARTMENT AND EXTINGUISHED THE SMALL FLAME. DAMAGE WAS LIMITED TO THE CNG FUEL TANK SOLENOID (MELTED) AND THE CONNECTING HARNESS (MELTED). THIS VEHICLE HAS A HIGH PRESSURE ELECTRONIC SHUT-OFF SOLENOID VALVE MOUNTED DIRECTLY TO THE ON-BOARD CNG FUEL TANK(S). NOTE: IF THERE IS A FUEL LEAK OR OTHER COMBUSTIBLE MATERIAL IN THE VICINITY, THERE IS A RISK OF IGNITION. DART HAS A TOTAL OF 123 EA., 2012 MODEL YEAR GM 6.0L CHEV EXPRESS SHUTTLE BUSES WHICH WERE PURCHASED FROM NATIONAL BUS SALES & LEASING BY DART. PRIOR TO DELIVERY, THE BUSES WERE MODIFIED BY ARBOC AND CONVERTED TO DEDICATED CNG OPERATION BY IMPCO AUTOMOTIVE IN UNION CITY, IN. EACH VEHICLE IS CONFIGURED WITH (2 EA.) LINCOLN 21' X 80' CNG CYLINDERS FITTED WITH OMB SOLENOID VALVES MOUNTED INSIDE AN ENCLOSED STORAGE COMPARTMENT BEHIND THE PASSENGER AREA. THERE WERE SIMILAR OCCURRENCES DOCUMENTED UNDER OTHER RECALL NOTIFICATIONS (GM BULLETIN #: 13139 AND IMPCO AUTOMOTIVE #: 13V-225); WHERE THE OEM IDENTIFIED ROOT CAUSES AND CORRECTIVE ACTIONS. UNDER THOSE GM AND/OR IMPCO REPORTS AND/OR DEFECT RECALLS REPORTED TO NHTSA, SIMILARLY, THE CONNECTOR TO THE CNG FUEL TANK EXPERIENCED HIGH-RESISTANCE SHORT IN THE CONNECTOR AND CAUSED OVERHEATING OR IN SOME INSTANCES A SELF-EXTINGUISHING FLAME.

TRAVELING AT 50 TO 55MPH I MAKE A EASY BRAKE APPLICATION AND THE FRONT WHEELS WILL START OSCILLATING UNTIL THE FRONT GOES INTO A VIOLENT SHAKE. RELEASING THE BRAKE WILL STOP THE SHAKING. THIS IS A CUTAWAY SCHOOL BUS. I'M THE MECHANIC AND THE DRIVER BROUGHT IT TO MY ATTENTION. SHE NOTICED IT WHILE BRAKING ON A DOWNHILL. I WAS ABLE TO DUPLICATE IT ON A LEVEL SURFACE. HAVEN'T FOUND THE FIX YET. *TR

THIS IS A BRAND NEW BUS, GM CHASSIS. IT HAS A LIMITED SLIP DIFFERENTIAL. THE BRAKE LINES ARE ROUTED IN FRONT OF THE REAR DIFFERENTIAL. TWICE, WE HAVE HAD ROCKS HIT THE BRAKE LINE AND SHEER IT OFF CAUSING TOTAL BRAKE FAILURE. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6). *TR