Some 1987 De Villes, Fleetwoods, Sevilles, Eldorados and Allantes may experience evaporator block fitting cracking. This condition may be caused by over torquing the evaporator block fitting bolt. It is extremely important not to exceed the 17 N.m (12 ft. lbs.) torque specification when tightening the evaporator block fitting bolt. Excessive torque may crack the block fitting necessitating replacement of the evaporator core.
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.