SPARK PLUG FOULING (INSTALL COPPER CORE PLUGS)

SPARK PLUG FOULING CAN BE REDUCED BY INSTALLING COPPER CORE PLUGS AND UTILIZING PROPER STARTING TECHNIQUES. COPPER CORE PLUGS ----------------- COPPER CORE PLUGS HAVE SHOWN TO BE SUPERIOR IN RESISTING SPARK PLUG FOULING. IN RECENT TESTING BY GM FOR MEDIUM DUTY TRUCKS, COPPER CORE PLUGS WERE 100% PLUS MORE EFFECTIVE IN RESISTING SPARK PLUG FOULING. COPPER CORE PLUGS HAVE BEEN RELEASED IN THE 6.0L (366) ENGINE. THE 4.8L (292), 5.7L (350), AND 7.0L (427) ENGINES WILL HAVE COPPER CORE PLUGS INSTALLED UPON CERTIFICATION. THE SERVICE PART NUMBER FOR THE 366 IS 5613933. APPLICATION 1980 THROUGH 1986* GAP 1.14 MM (.045) 14 MM (5/8 HEX) PLUG TORQUE 20 N.M (15 FT. LBS.) *COPPER CORE PLUGS CAN BE USED IN EARLIER APPLICATIONS UTILIZING 14 MM THREAD, 5/8 HEX, TAPERED SEAT SHELL DESIGN. ALL SERVICE PLUGS (5613933) ARE GAPPED AT .040". BE SURE TO REGAP THESE PLUGS AND TORQUE TO PROPER MODEL/YEAR/ENGINE SPECIFICATIONS. STARTING PROCEDURES ------------------- THE STARTING PROCEDURE HAS BEEN REVISED TO THE FOLLOWING. THIS CAN BE USED ON ALL MEDIUM DUTY GASOLINE ENGINE EQUIPPED VEHICLES WITH MANUAL CHOKES. ------------------------------------------------------------ GASOLINE ENGINE START PROCEDURE ------------------------------- APPLY PARKING BRAKE, PUT TRANSMISSION IN NEUTRAL, AND HOLD CLUTCH PEDAL DOWN, IF EQUIPPED. COLD ENGINE: ------------ PRESS ACCELERATOR ALL THE WAY AND PULL CHOKE OUT. RELEASE ACCELERATOR AND CRANK ENGINE TO START. AFTER ENGINE STARTS, PUSH CHOKE IN AS REQUIRED TO MAINTAIN SMOOTH FAST IDLE. WARM ENGINE: ------------ PRESS ACCELERATOR ONE-THIRD AND HOLD (CHOKE NOT REQUIRED). CRANK ENGINE TO START. NOTE: AT ENGINE SHUT DOWN, PUSH CHOKE IN AND ALLOW ENGINE TO RUN AT LEAST 5 SECONDS BEFORE TURNING KEY OFF. -------------------------------------------------------------

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.