For 1990-2009 cars

# DIESEL CRACKED CYLINDER HEAD CRACKS IN VALVE SEAT AREA

#### VEHICLES AFFECTED: All Vehicles Equipped With 5.7L or 4.3L Diesel Engines

We continue to hear about diesel cylinder heads are being replaced because of cracks between the intake and exhaust valve seats. Cracks in the seal area are normal for both the 5.7L and 4.3L diesel as well as some other diesel engines produced by other manufacturers. Many cylinder heads that have been returned to Oldsmobile has been examined and the cracks are superficial. The coolant in approximately five-eights of an inch away from the crack and therefore will not result in a loss of coolant or compression. Refer to Product Service Bulletin 1981 Group 60-124 for additional information.

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.