A SUDDEN HYDRAULIC PRESSURE LOSS DURING HARD TURNS RESULTS IN A MOMENTARY LOSS OF POWER STEERING ASSIST. THE PRESSURE LOSS OCCURS WHEN THE HYDRAULICALLY DRIVEN ENGINE COOLING FAN TURNS OFF IN THE TURN.
THE DRIVER REACTS TO THE LOSS OF POWER STEERING ASSIST BY OVERSTEERING, WHICH COULD RESULT IN A VEHICLE ACCIDENT.
THE HYDRAULIC CONTROL VALVES WILL BE REPLACED WITH VALVES OF A NEW DESIGN. UNTIL SUCH TIME AS PARTS ARE AVAILABLE, OWNERS WILL BE INSTRUCTED TO DISCONNECT THE FAN CUTOFF SWITCH SO THAT HYDRAULICALLY DRIVEN FANS WILL RUN FULL TIME, ELIMINATING THE PRESSURE SPIKE.
SYSTEM: ENGINE COOLING SYSTEM; FAN.VEHICLE DESCRIPTION: REAR ENGINE TRANSIT BUSES EQUIPPED WITH CATERPILLAR 3116, CUMMINS 6C 300 HP, OR HERCULES CNG ENGINES.NOTE: IF YOUR VEHICLE IS PRESENTED TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND THE REMEDY IS NOT PROVIDED WITHIN A REASONABLE TIME FREE OF CHARGE OR THE REMEDY DOES NOT CORRECT THE DEFECT, PLEASE CONTACT THOMAS BUILT AT 1-910-889-4871. ALSO, CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION'S AUTO SAFETY HOTLINE AT 1-800-424-9393.