For 1990-2009 cars

# ENGINE KNOCK - HT4100 DEFLASHED CRANKSHAFT AVAIL.

SOME CADILLACS EQUIPPED WITH AN HT4100 ENGINE MAY EXPERIENCE A KNOCKING CONDITION. TO CORRECT THIS CONDITION, A DEFLASHED CRANKSHAFT (P/N 1628920) HAS BEEN RELEASED FOR SERVICE. THIS CRANKSHAFT SHOULD ONLY BE USED IF THE KNOCK CONDITION IS PRESENT AFTER COMPLETING THE ITEMS OUTLINED IN 1983 PRODUCT SERVICE BULLETIN 6-127 DATED FEB. 15/83.

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.