For 1990-2009 cars

# SPARK PLUG SERVICE REPLACEMENT COATED PLUG P/N

#### VEHICLES AFFECTED: 1982-1988 CADILLACS WITH 4.1L OR 4.5L ENGINES

Beginning in the 1988 model year, a new AC spark plug has been released for all Cadillac 4.1L and 4.5L engines to improve the spark plug to spark plug boot interface. It is important that service technicians understand the reasons behind the selection of this new spark plug.

With the introduction of silicone spark plug wire boots several years ago, the tendency for a bonding or sticking condition to develop between the spark plugs and the spark plug boots began to arise. This condition arose because the silicone wire boot and the spark plug outer ceramic are similar materials. Exposure to underhood temperatures over periods of time had the tendency to increase the bond between the boot and the spark plug ceramic. In the past, different lubricative materials have been used in the spark plug boots with varying success. The new spark plug for 1988 was released to address this bonding condition.

1988 production spark plugs have a lubricative boot release coating baked onto the spark plugs ceramic outer surface. This coating is clear with a slightly waxy feel. To help identify the coated spark plug, the green rings were removed from the upper portion of the ceramic as a running change (Figure 1) . To further identify the new spark plug, the type number has been changed from .R44LTS6 to .R44LTS6K.

Test results have shown that the coating provides a significant reduction in spark plug boot release effort. Cadillac's 4.lL and 4.5L engines, along with the Oldsmobile Quad 4 engine, will be the only engines to use a coated plug of this type in 1988 production. In addition, Cadillac will be the only GM division to offer a coated spark plug for service use.

The coated spark plug, .R44LTS6K, will be available from GMSPO (P/N 5614158) for service use in all 1982-1988 4.1L and 4.5L engine applications. The coated service spark plug will be identical in appearance to the later style production spark plug (Figure 1). The existing spark plug, .R44LTS6, will continue to be available from GMSPO.

It is important that technicians wash their hands after handling coated spark plugs and before smoking. The coating itself is a non-hazardous material and incidental contact will not cause any adverse effects. However, exposure to polymer vapors -- the result of contamination of cigarette products and subsequent burning of the polymer -- may result in flu-like symptoms and should be avoided.

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.