INFO. ON USE OF LOW SULFUR DIESEL FUEL-LUBRICITY CONCERN. GMC Truck GMC Suburban

********************************************************************* SUBJECT: INFORMATION ON USE OF LOW SULFUR DIESEL FUEL -- LUBRICITY CONCERN

MODELS: 1982-94 CHEVROLET AND GMC C/K, R/V, P TRUCKS AND G VAN WITH 6.2L/6.5L DIESEL ENGINE (VINS C, J, P, S, Y, F) *********************************************************************

IN AUGUST 1990, THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY MANDATED THE USE OF LOW SULFUR DIESEL FUEL FOR ALL ON-HIGHWAY VEHICLES BEGINNING OCTOBER 1, 1993. RECENTLY, VARIOUS DIESEL EQUIPMENT MANUFACTURERS HAVE RAISED CONCERNS ABOUT THIS NEW FUEL, AS THE REFINING PROCESS USED TO REMOVE SULFUR **MAY** ALSO REMOVE OTHER COMPOUNDS PROVIDING LUBRICITY TO THE FUEL. TO ADDRESS THIS CONCERN, MANY DIESEL EQUIPMENT MANUFACTURERS HAVE REQUESTED THAT THE PETROLEUM INDUSTRY DEVELOP AND ENACT A LUBRICITY SPECIFICATION FOR DIESEL FUEL. UNTIL THIS LUBRICITY SPECIFICATION IS ENACTED, MANY DIESEL EQUIPMENT AND FUEL ADDITIVE MANUFACTURERS ARE RECOMMENDING THE USE OF LUBRICITY ENHANCERS TO ANYONE OPERATING ON-HIGHWAY DIESEL POWERED VEHICLES. GENERAL MOTORS, HOWEVER, DOES **NOT** BELIEVE THE USE OF THESE ADDITIVES IS NECESSARY IN OUR 6.2L/6.5L DIESEL ENGINES. THERE IS NO EVIDENCE THAT LOW SULFUR FUEL CAUSES ANY FUEL SYSTEM DAMAGE OR DRIVEABILITY CONCERNS IN THESE ENGINES.

LOW SULFUR DIESEL FUEL HAS BEEN MARKETED IN SOUTHERN CALIFORNIA FOR MORE THAN 5 YEARS WITHOUT CREATING ANY PROBLEMS FOR 6.2L/6.5L DIESEL POWERED VEHICLE OWNERS. GENERAL MOTORS HAS ALSO OPERATED DURABILITY AND DEVELOPMENT TEST VEHICLES WITH LOW SULFUR DIESEL FUEL FOR OVER TWO YEARS WITHOUT PROBLEMS.

FIGURES: 0

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.