ENGINE EXCHANGE PROGRAM. Chevrolet Corvette 1990

THIS BULLETIN IS BEING REVISED TO INFORM "GM OF CANADA" AND "NAES" DEALERS THAT THEY ARE NOT AUTHORIZED TO UTILIZE THIS SERVICE BULLETIN

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"GM OF CANADA" AND "NAES" DEALERS ARE NOT AUTHORIZED TO UTILIZE THIS SERVICE BULLETIN.

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THIS BULLETIN IS BEING REVISED TO ADD THE 1991-92 MODEL YEARS AND TO UPDATE SHIPPING INSTRUCTIONS.

REVISION 11/02/93

THIS BULLETIN HAS BEEN REVISED TO CONCLUDE THIS EXCHANGE PROGRAM.

PREVIOUS PUBLICATION NUMBERS WERE: CHEVROLET 92-228-6 GM OF CANADA 90-657-100

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SUBJECT: CONCLUSION OF THE ENGINE EXCHANGE PROGRAM FOR 1990-1994 5.7L LT5 V8 ENGINES (VIN CODE J)

MODELS: 1990-1994 CHEVROLET CORVETTE ZR1

INFORMATION ONLY

OVERVIEW

SINCE THE INTRODUCTION OF THE CORVETTE ZR1 IN 1990, CHEVROLET HAS CONTINUED TO RECEIVE POSITIVE COMMENTS FROM AUTOMOTIVE CRITICS WORLDWIDE. THE AREAS OF ENGINEERING, DESIGN, ROAD HANDLING, ACCELERATION RESPONSE, STYLING, AND EVEN THE OPERATING FEATURES HAVE BEEN ACCLAIMED AS "WORLD CLASS". IT IS IN THIS "WORLD CLASS" SPIRIT THAT WE MUST CONTINUE IN THE SERVICING OF THESE VEHICLES.

SINCE THE INTRODUCTION OF THE LT5 ENGINE A SPECIAL ENGINE EXCHANGE AND FACTORY REPAIR PROGRAM AT MERCURY MARINE WAS UTILIZED TO GAIN PRODUCT FEEDBACK. EFFECTIVE IMMEDIATELY, THE ENGINE EXCHANGE AND REPAIR PROGRAM FOR THE LT5 ENGINE IS CONCLUDED. ALL ENGINE REPAIRS WILL NOW BE PERFORMED IN-SHOP BY APPROVED ZR1 DEALERS. ALL TECHNICAL QUESTIONS AND DIAGNOSTIC CONCERNS ARE TO BE COMMUNICATED TO CHEVROLET TECHNICAL ASSISTANCE.

SPECIAL TOOLS

SPECIAL TOOLS REQUIRED TO SERVICE THE LT5 ENGINE WERE SHIPPED TO APPROVED DEALERS BEGINNING THE WEEK OF SEPTEMBER 20, 1993. IN THE EVENT A SPECIAL TOOL(S) IS NECESSARY BEFORE THE SHIPMENT ARRIVES, A CONSIGNMENT TOOL(S) CAN BE OBTAINED BY CALLING KENT-MOORE AT 1-800-345-2233. DUE TO THE LIMITED NUMBER OF TOOLS AVAILABLE, YOUR PROMPT RETURN OF THE CONSIGNED TOOL(S) IS ESSENTIAL. PLEASE NOTE THAT ONLY APPROVED ZR1 DEALERS WILL BE RECEIVING THE SPECIAL TOOL PACKAGE AND HAVE ACCESS TO THESE CONSIGNMENT TOOLS.

SERVICE PROCEDURES:

SERVICE MANUAL PROCEDURES ARE BEING REVISED TO INCLUDE ENGINE REMOVAL AND RE-INSTALLATION FOR ENGINE REPAIRS WHERE NECESSARY. A SERVICE MANUAL SUPPLEMENT HAS BEEN DEVELOPED TO UPDATE THE 1990-1993 LT5 SERVICE INFORMATION AND WILL BE PROVIDED UNDER SEPARATE COVER. ALL NEW INFORMATION WILL BE INCLUDED IN THE 1994 FINAL BOUND SERVICE MANUAL.

DEALERS THAT ARE NOT CURRENTLY APPROVED FOR ZR1 SALES AND SERVICE SHOULD CONTACT THE TECHNICAL ASSISTANCE NETWORK BEFORE PROCEEDING WITH ANY ENGINE REPAIR OTHER THAN NORMAL MAINTENANCE ITEMS. TO MAINTAIN THE INTEGRITY AND PRECISION OF THE LT5 ENGINE, PROPER DIAGNOSIS, REPAIR PROCEDURES AND SPECIAL TOOLS MUST BE USED. REPAIRS ATTEMPTED WITHOUT PROPER REPAIR TECHNIQUES AND TOOLS COULD RESULT IN POOR PERFORMANCE, AS WELL AS EXTENSIVE ADDITIONAL DAMAGE.

IN THE EVENT A MAJOR REPAIR IS REQUIRED TO THE ENGINE, TAN CAN ADVISE WHO THE NEAREST APPROVED ZR1 DEALER IS SO THE VEHICLE CAN BE TRANSPORTED FOR REPAIRS.

DUE TO THE DESIGN AND PRECISION OF THE LT5 ENGINE CAUTION MUST BE EXERCISED WHEN DIAGNOSING A PROBLEM SYMPTOM. CERTAIN DIAGNOSTIC RESULTS THAT MAY REPAIR A V8 ENGINE MAY NOT PROVE TO BE THE SAME REPAIR ON A LT5 ENGINE. TAN HAS DESIGNATED SPECIFIC REPRESENTATIVES TO ASSIST DEALERS WHEN DIAGNOSING THE LT5 ENGINE. CLOSE DEALER COMMUNICATIONS WITH TAN ON MOST LT5 ENGINE SERVICING WILL RESULT IN THE MOST EFFECTIVE REPAIR PROCEDURES.

IN THE EVENT A DEALER IS UNABLE TO SUCCESSFULLY REPAIR A LT5 ENGINE BY WORKING ALONG WITH TAN, A SPECIALIZED FIELD TECHNICIAN WILL BE AVAILABLE IN CONJUNCTION WITH THE CURRENT FIELD STAFF TO ASSIST THE DEALER. THIS SPECIALIZED TECHNICIAN WILL BE SCHEDULED FOR IN-DEALER REPAIRS THROUGH TAN AND THERE WILL BE A CHARGE TO THE DEALER FOR THIS SERVICE OUTSIDE OF THE WARRANTY COVERAGE.

THE LABOR TIME GUIDE (LTG) HAS BEEN REVISED TO PROVIDE A COMPLETE LIST OF LABOR OPERATIONS AND THE TIME FOR IN-DEALER SERVICING OF THE LT5 ENGINE.

PARTS

THE SUPPLY OF REPLACEMENT PARTS FOR THE LT5 ENGINE WAS DEVELOPED BASED ON THE HISTORY OF REPAIRS SINCE ITS INTRODUCTION. WHILE THE STOCK IS ADEQUATE TO SERVICE CUSTOMERS' IMMEDIATE NEEDS, EVERY EFFORT MUST BE MADE TO ORDER ONLY THE PARTS REQUIRED TO COMPLETE A SPECIFIC REPAIR. SOME OF THE COMPONENTS USED ON THE LT5 ENGINE ARE PECULIAR TO THIS ENGINE AND WERE ACQUIRED ON AN AS NEEDED BASIS, THEREFORE, THE CURRENT QUANTITY AVAILABLE FOR SERVICE IS MINIMAL. THESE UNIQUE PARTS WILL BE MONITORED BY GM SERVICE PARTS OPERATION (SPO). TAN WILL REVIEW THE REQUEST AND DIAGNOSTICS WITH THE DEALER AND CONTACT SPO TO RELEASE THE PARTS AS REQUIRED. A PROCESS HAS BEEN ESTABLISHED TO ACCOMPLISH THIS REVIEW AND PREVENT ANY UNNECESSARY DELAYS TO THE DEALER FOR COMPLETING THE REPAIRS. SOME OF THE PARTS THAT WILL BE MONITORED ARE ENGINE ASSEMBLIES, ENGINE BLOCKS, CRANKSHAFTS, CYLINDER HEADS, ETC.

TO IDENTIFY PARTS THAT ARE NEEDED, DEALERS SHOULD USE THE 1993-94 ILLUSTRATIONS FOR ALL MODEL YEARS. THE PARTS LISTINGS ARE THEN USED TO ACQUIRE THE CORRECT PART NUMBER AS IDENTIFIED BY MODEL YEAR.

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.