Field returned oil pans indicate damage and/or cracks have occurred when supporting or lifting the engine at the oil pan with jacking equipment or when applying pressure to the side of the pan (such as in prying on the pan to align mounts).
The only recommended method to support or lift the engine for front cover or other repairs where the front of the engine needs to be supported or lifted, is to use engine support fixture J 28467-A. Use of any other method is not recommended!
However, if J 28467-A is not available and the engine is being supported or lifted by the oil pan, a 2' x 4' block of wood must be used between the oil pan and the jacking equipment to avoid cracking the oil pan. Be sure the 2" x 4' block of wood extends beyond the edges of the oil pan to provide an even load distribution across the oil pan. Refer to the illustration below.
DO NOT LIFT VEHICLE BY THE OIL PAN; this will cause the oil pan to crack. Refer to Section OA of the applicable service manual for lifting and jacking points and procedures.
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.