OIL LEAKS BETWEEN INTAKE MANIFOLD & ENGINE BLOCK

SUBJECT: OIL LEAKS BETWEEN INTAKE MANIFOLD AND ENGINE BLOCK (RESEAL THE MATING SURFACES)

MODELS: 1992-96 CHEVROLET CORVETTE 1993-97 CHEVROLET CAMARO 1993-97 PONTIAC FIREBIRD WITH 5.7L ENGINE (VINS P, 5 - RPOS LT1, LT4)

CONDITION:

OIL LEAKS AT MATING SURFACES BETWEEN THE INTAKE MANIFOLD AND ENGINE BLOCK. SOMETIMES CALLED "CHINA WALL." (SEE FIGURES 1 AND 2)

CAUSE:

INSUFFICIENT RTV BONDING BETWEEN THE INTAKE MANIFOLD AND CYLINDER BLOCK.

CORRECTION:

IT IS VERY IMPORTANT TO IDENTIFY THE SOURCE OF THE LEAK. CLEAN AND DRY AREA THOROUGHLY BEFORE INSPECTION. USE BLACK LIGHT AND OIL DYE TO IDENTIFY THE SOURCE. IF THE CHINA WALL AREA IS FOUND TO BE THE SOURCE OF THE LEAK, RESEAL THE MATING SURFACES WITH "3 BOND" RTV (P/N 12346141).

WE BELIEVE THIS SOURCE AND THEIR PRODUCT TO BE RELIABLE. THERE MAY BE ADDITIONAL MANUFACTURERS OF SUCH PRODUCTS. GENERAL MOTORS DOES NOT ENDORSE, INDICATE ANY PREFERENCE FOR OR ASSUME ANY RESPONSIBILITY FOR THE PRODUCTS FROM THIS FIRM OR FOR ANY SUCH ITEMS WHICH MAY BE AVAILABLE FROM OTHER SOURCES.

IT IS EXTREMELY IMPORTANT THAT THE MATING SURFACES BE PROPERLY CLEANED BEFORE APPLYING THE RTV.

SCRAPE OFF ORIGINAL SEALER AND ANY FOREIGN MATERIAL FROM THE INTAKE MANIFOLD AND ENGINE BLOCK. AVOID SCRATCHING SURFACES AND DO NOT ALLOW ANY DEBRIS TO FALL INTO THE ENGINE. DO NOT USE ANY TYPE OF HIGH SPEED ROTARY DISCS.

WIPE SURFACES CLEAN WITH A CLEAN DRY CLOTH AND CLEANER SOLVENT. PAY PARTICULAR ATTENTION TO THE FOUR CORNERS WHERE THE HEADS MEET THE FRONT AND REAR CHINA WALL AREA OF THE BLOCK. AGAIN ENSURE THAT PARTICLES DO NOT FALL INTO THE ENGINE. WIPE SURFACES CLEAN WITH A CLEAN DRY CLOTH AND CLEANER SOLVENT.

PRIME THE MATING SURFACES WITH THE NEW RTV SEALANT BY RUBBING THE SURFACES WITH A SMALL AMOUNT OF WET RTV ON A CLEAN CLOTH. THEN WIPE OFF THE EXCESS RTV.

FIRMLY APPLY A 1/4 INCH (5MM) DIAMETER BEAD OF RTV INTO EACH OF THE FOUR CORNERS WHERE THE HEADS MEET THE BLOCK. THEN, APPLY A 1/4 INCH (5MM) BEAD OF RTV TO THE FRONT AND REAR AREAS OF THE ENGINE BLOCK, GOING UP THE CYLINDER HEADS APPROXIMATELY 3/8 TO 1/2 INCH (10 TO 12.7MM). (SEE FIGURES 1 AND 2)

WHILE RTV IS STILL WET, INSTALL THE INTAKE MANIFOLD AND GASKETS PER SERVICE MANUAL PROCEDURES. TAKE CARE NOT TO PUSH THE RTV OUT OF POSITION. AFTER ASSEMBLING THE ENGINE, LET RTV CURE FOR AT LEAST 2 HOURS BEFORE DRIVING VEHICLE.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE: LABOR OP: J0200 USE PUBLISHED LABOR OPERATION TIME.

INSERT PICTURE #2906T9056

FIGURE 1

INSERT PICTURE #2906T9054

FIGURE 2

FIGURES: 2 ATTACHMENTS: 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.

COPYRIGHT 1997. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.