Engine - Oil Leaks Between Intake Manifold and Block
File In Section: 6.- EngineBulletin No.: 77-61-17
Date: October, 1997
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 (5 mm) diameter bead of RTV into each of the four corners where the heads meet the block. Then, apply a 114 inch (5 mm) 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 12.7 mm). (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 Operation Labor Time
J0200 Use published labor
operation time