IDLE EXH. BOOM/HT4100 ENGINE INSTALL WEIGHTS/EXHAUST PIPE

SOME 1983 C-CARS EQUIPPED WITH HT4100 ENGINES MAY EXHIBIT AN EXHAUST BOOM AND VIBRATION DURING IDLE AND/OR OFF IDLE OPERATION. THIS BOOM CAN OCCUR AT ENGINE SPEEDS FROM 550 RPM TO 620 RPM AND WILL USUALLY PEAK AT APPROXIMATELY 580 RPM. A SPECIFIC EXHAUST WEIGHT (P/N 1627662) HAS BEEN RELEASED FOR SERVICE TO CORRECT THIS CONDITION. TWO WEIGHTS ARE REQUIRED PER CAR AND SHOULD BE INSTALLED ON THE EXHAUST PIPE AT THE LOCATIONS SHOWN IN THE ILLUSTRATION BELOW USING TWO APPROPRIATELY SIZED STAINLESS STEEL HOSE CLAMPS PER WEIGHT. FOR WARRANTY PURPOSES, USE OPERATION NUMBER T6072 AT .3 HOUR. (CADILLAC)

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.