000601012J

Bulletin No.:
Service Bulletin
Date:
00-06-01-012J
June, 2019
INFORMATION
Subject:
Use of Surface Conditioning Disks When Cleaning Gasket Sealing Surfaces and/or
Reused Parts
Models:
2020 and Prior GM Passenger Cars and Trucks including Silverado 4500HD, 5500HD
and 6500HD (Excluding Chevrolet Medium Duty Low Cab Forward Equipped with
Diesel Engine).
Attention: This Bulletin also applies to any of the above models that may be North America
Export vehicles.
This Bulletin has been revised to add Model Year 2020 vehicles. Please discard Corporate
Bulletin Number 00-06-01-012I.
The Use of Surface Conditioning Disks
2726943
Copyright 2019 General Motors LLC. All Rights Reserved.
Notice: Do not use abrasive pad/bristle devices to
clean the gasket surfaces of any engine, transmission,
transfer case and axles as well as any other component
that contains lubricant. Abrasive pads should not be
used for some of the following reasons:
• Abrasive pads will produce fine grit that the oil filter
will not be able to remove from the oil. THIS GRIT
IS ABRASIVE AND HAS BEEN KNOWN TO
CAUSE INTERNAL ENGINE DAMAGE. Abrasive
pads can easily remove enough material to round
cylinder head surfaces. This has been known to
affect the gasket's ability to seal, especially in the
narrow seal areas between the combustion
chambers and coolant jackets.
• Abrasive pads, wire and abrasive rubber finger
wheels can also remove enough metal to affect
cylinder head, block, oil pan rail, and intake
manifold runner flatness, which can cause coolant
and oil leaks and air leaks. It takes about
15 seconds to remove 0.203 mm (0.008 in) of
metal with an abrasive pad.
• Abrasive pads, Abrasive rubber fingers wheels &
wire wheels with high speeds grinders produce
airborne debris that can travel throughout the shop
contaminating other work being performed outside
of the immediate work area.
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The use of an abrasive hand pads and/or steel wool
can also create imperfections in the metal and therefore
are not recommended for use when cleaning surfaces.
When cleaning gasket sealing surfaces and/or cleaning
parts that are to be reused, surface conditioning disks,
hand pads, or steel wool (typically constructed of
woven fiber, steel or molded bristles) that contain
abrasives, such as a high amount of Aluminum Oxide,
should NOT be used.
The use of such surface conditioning items dislodges
Aluminum Oxide (from the disk) and metal particles
(from steel wool), which can lead to premature engine
bearing failure.
Examples
Bulletin No.: 00-06-01-012J
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4788796
The presence of Aluminum Oxide in engine oil has
been shown to cause premature engine bearing failure.
In some cases, this failure occurs in as little as
2,200 km (1,367 mi) or less after the repair has
been made.
The scratches on the bearings in the above picture
were created when debris from an abrasive pad made
its way into the bearing. This debris is a combination of
the metal and particles from the abrasive pad that were
removed when the engine was cleaned.
Surface conditioning disks may grind the component
material and imbed it into the disk. This can result when
more aggressive grinding of the gasket surface takes
place.
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The crankshaft deflector in the picture above has debris
that was left behind from the abrasive cleaning
methods. Once the debris has gotten here, it can be
distributed to any surface in the engine.
Recommended Cleaning Procedure
General Motors recommends the use of a razor blade
or plastic gasket scraper to clean the gasket surface on
components that are to be reused. When cleaning
gasket surfaces, please note the following:
• When using a razor blade type gasket scraper,
use a new razor blade for each cylinder head and
corresponding block surface. Hold the blade as
parallel to the gasket surface as possible. This will
ensure that the razor blade does not gouge or
scratch the gasket surfaces.
• Do not gouge or scrape the combustion chamber
surfaces.
• Do not gouge or scratch any engine-sealing
surface during the cleaning process.
Alternative Cleaning Method:
To properly clean the sealing surface prior to
reassembly, GM Low VOC Cleaner, P/N 19287401,
in Canada, P/N 88901247 and in Australia,
P/N 88900163, should be sprayed on the mating
surface. Use care to avoid getting solvent in any area
other than the mating surface to be cleaned. Allow it to
soak in for several minutes to loosen the old RTV
sealer/gasket material. GM strongly recommends using
a plastic razor blade or non- metallic scraper to remove
all loose sealer/gasket material.
Important: The appearance of the gasket surface is
not critical - the feel is. There will be indentations from
the gasket left after all the gasket material is removed.
The new gasket will fill these small indentations when it
is installed.
Bulletin No.: 00-06-01-012J
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Page 5
Information on Non-Recommended
Abrasive Pad/Bristle Surface
Conditioning Disks
Important: Dealers who use improper gasket cleaning
methods resulting in component failures will be debited
the cost of the replacement and repair, and possibly
considered for restriction with future replacements.
4788615
An overview of the deck face when it has been cleaned
with an abrasive pad, left swirls on the surface and do
not go in the same direction, which caused changes in
the surface dimensions (flatness) of the block leaving it
un-usable.
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Scratches from the pad are deeper in some areas than
others causing the gasket/seals not to properly seal
against an uneven surface.
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4788657
Note: Damage to the pistons and/or cylinder walls may
result in an engine knocking, tapping and/or possible
low compression.
The sides of this cylinder wall were scarred with
scratches as a result of the debris created by the
abrasive cleaning pads. This debris gets trapped
between the piston head and the cylinder wall causing
damage to the cylinder bore as the piston moves up
and down.
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The piston skirt and piston ring damage caused by
abrasive cleaning pads.
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Page 9
Surface Preparation
4791153
A close up of the sealing surface after cleaned with
GM Low VOC Cleaner and plastic scraper.
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A close-up of the surface shows deep grooves caused
by using an abrasive cleaning disc.
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4791276
A close-up of the surface shows deep grooves caused
by use of a wire wheel.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
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 your GM dealer for information on whether your vehicle may benefit from the
information.
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