2012 MACK LEU

ENGINE AND ENGINE COOLING:ENGINE

Mack Trucks, Inc. (Mack) is recalling certain model year 2011-2016 Mack MRU and LEU trucks manufactured June 25, 2010, to April 30, 2015, and 2015-2016 LR6 trucks manufactured from December 18, 2014 through March 6, 2015. Excessive engine crankcase pressures may cause the 90-degree elbow of the vent tube assembly to detach from the crankcase ventilation breather, possibly allowing engine oil to come into contact with hot surfaces.

Risk: If engine oil comes into contact with a hot surface, there could be an increased risk of a fire.

ENGINE AND ENGINE COOLING:EXHAUST SYSTEM

Mack Trucks, Inc. (Mack) is recalling certain model year 2010-2015 LEU vehicles manufactured May 14, 2009, through February 14, 2014, and equipped with a Cummins ISL engine. In the affected vehicles, the exhaust pipe may disconnect from the muffler/catalyst.

Risk: If the exhaust pipe separates from the muffler on a twin-steer configured vehicle where the vehicle is operated from the right side, the operator may be exposed to carbon monoxide levels which may cause personal injury.

EXTERIOR LIGHTING:TURN SIGNAL:FLASHER UNIT

Mack Trucks Inc. (Mack) is recalling certain model year 2010-2014 CHU, CXU, and MRU, 2007 CT and CV, 2008-2014 GU, and 2011-2014 LEU, and TD trucks manufactured February 28, 2006, through November 8, 2013, and equipped Hamsar Electronic Flasher. The hazard warning lights may fail.

Risk: A failure of the hazard warning lights could reduce the trucks visibility, increasing the risk of a crash.

ENGINE AND ENGINE COOLING:ENGINE

Mack Trucks Inc. (Mack) is recalling certain model year 2014-2015 CXU, 2010-2015 LEU, and 2011-2015 MRU vehicles manufactured with certain Cummins Westport Model ISL G and ISX12 G engines. Condensation in the intake manifold may freeze during cold weather conditions and interfere with the proper operation of the intake manifold pressure sensor.

Risk: The improper operation of the sensor could induce elevated exhaust temperatures or flames from the exhaust pipe, increasing the risk of a vehicle fire or burn injury to a person near the exhaust pipe.

ELECTRICAL SYSTEM:ALTERNATOR/GENERATOR/REGULATOR

MACK IS RECALLING CERTAIN MODEL YEAR 2010-2012 LEU AND MODEL YEAR 2011-2012 MRU VEHICLES, MANUFACTURED FROM MAY 14, 2009, THROUGH OCTOBER 31, 2011, AND BUILT TO OPERATE ON COMPRESSED NATURAL GAS. ON THESE VEHICLES THE ALTERNATOR GROUND CABLE RUNS DIRECTLY TO THE STARTER, WHICH DEFEATS THE CIRCUIT PROTECTION.

Risk: IN THE EVENT OF AN ELECTRICAL SHORT, A VEHICLE FIRE MAY RESULT.

ELECTRICAL SYSTEM

MACK TRUCKS IS RECALLING CERTAIN MODEL YEAR 2008-2012 MRU AND LEU HEAVY TRUCKS MANUFACTURED FROM JANUARY 3, 2007, THROUGH FEBRUARY 3, 2011. THE ELECTRICAL CIRCUITRY IN THESE VEHICLES MAY NOT PROVIDE ADEQUATE OVERCURRENT PROTECTION.

Risk: IN THE EVENT OF AN ELECTRICAL OVERAGE, THE FUSE THAT SHOULD PREVENT THE OVER CURRENT FROM REACHING THE MIRROR SWITCH CIRCUIT MAY FAIL, SUCH THAT THE MIRROR SWITCH CAN OVERHEAT. AN OVERHEATED SWITCH COULD CAUSE A VEHICLE FIRE.

POWER TRAIN:DRIVELINE

MACK TRUCKS IS RECALLING CERTAIN MODEL YEAR 2012, CHU, CXU, GU, MRU, LEU, AND TD TRUCKS EQUIPPED WITH A MERITOR DRIVELINE. THE TUBING USED TO ASSEMBLE THE AFFECTED DRIVELINES HAS A NONCONFORMING SEAM WELD WITH INSUFFICIENT BONDING OF THE MATERIAL.

Risk: THIS CAN RESULT IN SEAM WELD FRACTURE WHEN TORQUE IS APPLIED. ONCE THE TUBE SEAM WELD IS FRACTURED, THE DRIVELINE MAY BECOME INOPERABLE WHICH MAY RESULT IN A DISABLED VEHICLE OR DEBRIS FROM THE DRIVELINE MAY FALL ON THE ROADWAY, BOTH OF WHICH CAN INCREASE THE RISK OF A CRASH.