WATER CONTAMINATION OF ENGINE OIL. Chevrolet Export Express 1997

For 1990-2009 cars

# WATER CONTAMINATION OF ENGINE OIL

#### SUBJECT: WATER CONTAMINATION OF ENGINE OIL (SEAL FRESH AIR INLET PLENUM SEAM AND CHANGE ENGINE OIL)

#### MODELS: 1996-97 CHEVROLET G VAN MODELS BUILT BEFORE VIN BREAKPOINT V1041149 1996-97 GMC G VAN MODELS BUILT BEFORE VIN BREAKPOINT V1041098 WITH 5.0L AND 5.7L ENGINES (VINS M, R - RPOS L30, L31)

#### CONDITION:

AN OWNER MAY REPORT THE ENGINE OIL IS MILKY COLORED AND/OR THE ENGINE IS NOISY, OR HAS LOW OR NO OIL PRESSURE. IN BELOW FREEZING TEMPERATURES, THE ENGINE OIL FILTER MAY BE BALLOONED AND/OR LEAKING AT THE SEAL.

#### CAUSE:

THERE MAY BE A LEAK IN THE FRESH AIR INLET PLENUM WHICH COULD WATER TO DRAIN ONTO THE ENGINE OIL DIPSTICK TUBE. THE WATER CAN THEN ENTER THE ENGINE AND CONTAMINATE THE OIL THROUGH A JUNCTION OF THE OIL DIPSTICK TUBE EXTENSION.

#### CORRECTION:

VERIFY WHETHER THIS CONDITION EXISTS BY PERFORMING THE FOLLOWING TEST. WITH THE HOOD OPEN, POUR APPROXIMATELY 16 OZ. OF WATER INTO THE LEFT SIDE OF THE AIR INLET SCREEN, NEAR THE CENTER OF THE WINDSHIELD (FIGURE 1). OBSERVE WHETHER WATER LEAKS THROUGH THE PLENUM SEAM (FIGURE 2). IF WATER DOES LEAK THROUGH THE PLENUM SEAM, FOLLOW THE STEPS IN THE PLENUM SEALING PROCEDURES. IF NO WATER LEAK IS OBSERVED FROM THE PLENUM SEAM, CONTINUE THE STEPS OF STRATEGY BASED DIAGNOSTICS FOR THE SYMPTOM AS DESCRIBED IN THE SERVICE MANUAL.

SERVICE PROCEDURE

PLENUM SEALING PROCEDURE

1. CYCLE THE WINDSHIELD WIPERS SO THAT THE WINDSHIELD WIPER ARMS ARE IN THE VERTICAL (UPWARD) POSITION AND THEN REMOVE THE RH (PASSENGER SIDE) WINDSHIELD WIPER ARM FOLLOWING THE PROCEDURE IN SECTION 8E OF THE SERVICE MANUAL.

2. OPEN THE HOOD AND REMOVE THE LH (DRIVERS SIDE) AIR INLET SCREEN (ATTACHED BY 4 SCREWS AND 1 CLIP). CAREFULLY MOVE THE AIR INLET SCREEN OUT OF THE WAY TO ACCESS THE PLENUM CAVITY.

3. CLEAN AND DRY THE AREA ON THE INSIDE OF THE PLENUM CAVITY WHERE THE WATER LEAK EXISTS.

4. SEAL THE LEAK AREA USING RTV SILICONE SEALER P/N 12346286 OR EQUIVALENT.

5. VERIFY THAT WATER DOES NOT LEAK THROUGH THE PLENUM SEAM.

6. INSTALL THE LH AIR INLET SCREEN.

7. CYCLE THE WINDSHIELD WIPER ARM TO THE PARKED POSITION. INSTALL RH WINDSHIELD WIPER ARM FOLLOWING THE PROCEDURE IN SECTION 8E OF THE SERVICE MANUAL.

8. CHANGE ENGINE OIL AND FILTER USING PART NUMBERS AND PROCEDURES IN OWNER'S MANUAL AND SERVICE MANUAL.

PART INFORMATION

P/N DESCRIPTION QTY 12346286 SEALER, RTV SILICONE 1

PART IS CURRENTLY AVAILABLE FROM GMSPO.

#### WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP DESCRIPTION LABOR TIME C0010 COWL AREA - RESEAL USE PUBLISHED LABOR OPERATION TIME

OTHER LABOR HOURS - 0.5 HOURS TO CHANGE ENGINE OIL AND FILTER. REQUIRES AUTHORIZATION.

#### IMPORTANT: LABOR OPERATION IS CODED TO BASE VEHICLE COVERAGE IN THE WARRANTY SYSTEM.

FIGURES: 2

CAPTIONS: 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. *****DISCLAIMER*****

COPYRIGHT 1997 GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.