SLOW HEATER WARM-UP OR INADEQUATE HEATER. Oldsmobile Achieva 1992

SUBJECT: SLOW HEATER WARM-UP OR INADEQUATE HEATER PERFORMANCE DURING ENGINE IDLE (REPLACE FLOOR AIR OUTLET AND FLUSH HEATER CORE)

MODELS: 1992-93 BUICK SKYLARK 1992-93 OLDSMOBILE ACHIEVA 1992-93 PONTIAC GRAND AM WITH 2.3L ENGINE (VIN D - RPO LD2; VIN 3 - RPO L40) AND 3.3L ENGINE (VIN N - RPO LG7)

THIS BULLETIN CANCELS AND SUPERSEDES BULLETIN 331102 (GROUP REFERENCE 1 - HVAC).

CONDITION:

SOME OWNERS MAY COMMENT ON A CONDITION WHERE THE HEATER AIR IS SLOW TO WARM UP OR THE HEATER OUTLET AIR DURING IDLE IS NOT WARM ENOUGH.

CAUSE:

SOME VEHICLES MAY EXHIBIT A CONDITION WHERE THE AIR FLOW FROM THE FLOOR AIR OUTLET DOES NOT PROVIDE ENOUGH CIRCULATION TO THE FRONT OF THE PASSENGER COMPARTMENT. A NEW FLOOR AIR OUTLET HAS BEEN DESIGNED TO REDIRECT AIR FLOW TO THE FRONT SEAT AND TO DISTRIBUTE AIR MORE EVENLY ACROSS THE FLOOR.

ALSO, SOME ENGINE CORE SAND MAY HAVE ACCUMULATED IN THE HEATER CORE, RESULTING IN REDUCED COOLANT FLOW. A BACKFLUSH OF THE HEATER CORE ONLY WILL REMOVE THIS DEBRIS.

TO FURTHER ASSIST VEHICLES EQUIPPED WITH VIN D AND 3 ENGINES, A NEW 205 DEGREE FAHRENHEIT (96 DEGREE CELSIUS) THERMOSTAT HAS BEEN DEVELOPED. FOR VEHICLES EQUIPPED WITH VIN D AND 3 ENGINES, FEDERAL EMISSIONS ONLY, A NEW EPROM HAS BEEN CALIBRATED TO INCREASE COLD WEATHER IDLE BOOST. THIS ELEVATED IDLE INCREASES WATER TEMPERATURE AND FLOW THROUGH THE HEATER CORE, THUS IMPROVING PERFORMANCE.

CORRECTION:

VEHICLES EQUIPPED WITH VIN D AND 3 ENGINES WITH FEDERAL EMISSIONS:

1. REPLACE THERMOSTAT. 2. REPLACE FLOOR AIR OUTLET. 3. REPLACE EPROM. 4. FLUSH HEATER CORE.

VEHICLES EQUIPPED WITH VIN D AND 3 ENGINES WITH CALIFORNIA EMISSIONS:

1. REPLACE FLOOR AIR OUTLET. 2. FLUSH HEATER CORE.

VEHICLES EQUIPPED WITH VIN N ENGINE, EITHER CALIFORNIA OR FEDERAL EMISSIONS:

1. REPLACE FLOOR AIR OUTLET. 2. FLUSH HEATER CORE.

SERVICE PROCEDURE:

HEATER CORE FLUSH -

1. DISCONNECT HEATER HOSES FROM HEATER CORE. 2. BACKFLUSH HEATER CORE. 3. RECONNECT HEATER HOSES.

FOR THERMOSTAT, FLOOR AIR OUTLET, AND EPROM SERVICE PROCEDURES, REFER TO THE APPROPRIATE SERVICE MANUAL.

PARTS INFORMATION:

IMPORTANT: THE FOLLOWING KIT NUMBERS CONTAIN THE PARTS NEEDED TO PERFORM THIS PROCEDURE. THE EPROM NUMBERS ARE FOR REFERENCE ONLY.

KIT NUMBERS:

1992 L40 FEDERAL EMISSIONS 22646937 1992 LD2 FEDERAL EMISSIONS 22646938 1993 L40 FEDERAL EMISSIONS 22646939 1993 LD2 FEDERAL EMISSIONS 22646940 1992-93 L40/LD2 CALIFORNIA EMISSIONS 22646941 1992-93 LG7 ALL EMISSIONS 22646941

EPROM PART NUMBERS:

DIVISION/ ENGINE VIN/ BROADCAST SCAN PART YEAR MODEL TRANS EMISSION CODE I.D. NUMBER ==== ========= =========== ======== ========= ==== ======

1992 2,3,4 N L40/3AMT FEDERAL BNUP 5563 16215577 1992 2,3,4 N LD2/3AMT FEDERAL BNUR 5573 16215579 1993 2,3,4 N L40/3AMT FEDERAL BNUS 5583 16215581 1993 2,3,4 N LD2/3AMT FEDERAL BNUT 5593 16215584

PARTS ARE EXPECTED TO BE AVAILABLE ON MARCH 20, 1995.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION NUMBER: D2813 (THERMOSTAT, FLOOR AIR OUTLET, EPROM, HEATER CORE FLUSH) LABOR TIME: 1.6 HR. (2.3L ENGINES W/FEDERAL EMISSIONS)

LABOR OPERATION NUMBER: D2813 (THERMOSTAT, FLOOR AIR OUTLET, HEATER CORE FLUSH) LABOR TIME: 1.4 HR. (2.3L ENGINES W/CALIFORNIA EMISSIONS)

LABOR OPERATION NUMBER: D2813 (FLOOR AIR OUTLET, HEATER CORE FLUSH) 1.0 HR. (ALL 3.3L ENGINES)

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.