For 1990-2009 cars

# HEAD GASKET REPLACEMENT SURFACE TREATMENT INFORMATION

#### MODELS AFFECTED: ALL MODELS

Production cylinder head gaskets are installed without the addition of any surface treatments or adhesion promoters. Service head gaskets should be installed without any extra sealing aids. Head gasket dressings do not increase sealing capacity and, in some cases, may actually be detrimental to the gasket's usefulness. Using a head gasket (without any extra sealant) between clean mating surfaces as well as following proper head bolt torquing procedure will yield an adequate seal in this area. This bulletin is for information only.

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.