ENG. LOW COOLANT LIGHT COMING ON WHEN PARKED DOWNHILL OR ON. Chevrolet Corvette 1998

SUBJECT: ENGINE LOW COOLANT LIGHT COMING ON WHEN PARKED DOWNHILL OR ON LEVEL SURFACE (REPLACE AND/OR REPOSITION COOLANT SURGE TANK)

MODELS: 1997-98 CHEVROLET CORVETTE - 1997 MODELS BUILT PRIOR TO VIN BREAKPOINT 104277

CONDITION:

SOME CUSTOMERS MAY COMMENT THAT THE ENGINE "LOW COOLANT" LIGHT COMES ON AT START-UP. THIS CONDITION WILL MOST LIKELY OCCUR WHEN THE VEHICLE IS PARKED DOWNHILL OR ON A LEVEL SURFACE.

CAUSE:

THIS CONDITION MAY BE CAUSED DUE TO THE LOW COOLANT SENSOR BEING MOUNTED IN THE REAR OF THE RADIATOR SURGE TANK AND IS IN THE SHALLOW END OF THE COOLANT. THE "LOW COOLANT" LIGHT MAY COME ON IF:

- THE VEHICLE WAS BUILT PRIOR TO VIN BREAKPOINT WITH THE OLD DESIGN SURGE TANK.

- THE RADIATOR SURGE TANK IS NOT INSTALLED LEVEL IN THE VEHICLE.

- THE RADIATOR SURGE TANK IS NOT FILLED PROPERLY.

- THE FLOAT IN THE TANK IS STICKING.

- THE COOLANT SWITCH CONNECTOR IS IMPROPERLY SEATED ON THE SWITCH.

CORRECTION:

1. FOR VEHICLES BUILT PRIOR TO VIN BREAKPOINT 104277, REPLACE THE RADIATOR SURGE TANK AND INSPECT FOR AN OUT OF POSITION WIRING HARNESS UNDER THE TANK. TO REPAIR THE HARNESS, POSITION THE HARNESS DOWNWARD AND SECURE WITH A TIE STRAP. TANKS CAN BE IDENTIFIED BY THE PART NUMBER ON THE BOTTOM. IF THE RADIATOR SURGE TANK IS P/N 10229487, IT SHOULD BE REPLACED WITH P/N 10405218, FOLLOWING THE PROCEDURES IN THE SERVICE MANUAL.

CAUTION:

SEE SERVICE MANUAL ON PRESSURIZED COOLING SYSTEMS.

2. FOR ALL OTHER VEHICLES, CHECK THE LEVEL OF THE TANK BY VIEWING THE LOWER MOUNT ON THE TANK (SEE FIGURE 1). THE MOUNTING SLOT SHOULD ONLY BE VISIBLE BY NO MORE THAN 2 MM (.08 IN) ABOVE THE ATTACHING NUT. IF THE GAP IS GREATER THAN 2 MM (.08 IN), LOOSEN THE SURGE TANK AND HOLD DOWNWARD IN POSITION TO ACHIEVE THE LESS THAN 2 MM (.08 IN) GAP ABOVE THE ATTACHING NUT. TIGHTEN THE BOTTOM NUT FIRST, THEN BOTH TOP NUTS TO 10 N.M (89 LB IN).

3. RE-CHECK COOLANT LEVEL IN SURGE TANK.

- IF HOT, FILL WITH COOLANT 12 MM (1/2 IN) ABOVE INDICATOR MARK.

- IF COLD, FILL WITH COOLANT TO TOP OF INDICATOR MARK.

PARTS INFORMATION:

P/N DESCRIPTION =================== ====================================

10405218 TANK ASSEMBLY, RADIATOR SURGE

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION LABOR OPERATION NUMBER DESCRIPTION TIME =============== ================================= ===============

J3250 TANK, RADIATOR COOLANT SURGE 0.2 HR REPOSITION

J3250 TANK, RADIATOR COOLANT SURGE USE PUBLISHED R + R OR REPLACE LABOR OPERATION TIME

ADD: HARNESS, REPOSITION 0.1 HR

FIGURES: 01 ATTACHMENTS: 00

FIGURE 1 1. 2 MM (.08 IN) OR LESS

Object Number: 484245 Size: FS

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.