Bulletin No.:

Service Bulletin

Date:

00-06-01-026M
August, 2019

INFORMATION
Subject:

Engine Replacement After Severe Internal Engine Damage – Replace Intake Manifold

Models:

2020 and Prior GM Passenger Cars and Trucks (including Medium Duty)
Equipped with Gasoline, CNG or LPG Engine

Attention: This Bulletin also applies to any of the above models that may be Export from North
America vehicles.
This Bulletin has been revised to combine information from Corporate Bulletin Number
06-06-01-010D and add the 2020 Model Year. Please discard Corporate Bulletin Numbers
06-06-01-010D and 00-06-01-026L.

General Information
•

•

•

When replacing an engine due to internal damage,
extreme care should be taken when transferring
the intake manifold to the new Genuine GM Part
service engine long block. The internal engine
damage may have resulted in the potential
discharge of internal engine component debris
into the intake manifold via broken pistons and/or
bent, broken, or missing intake valves.
After removing the intake manifold from the
engine, the technician MUST carefully inspect all
of the cylinder head intake ports to see if the valve
heads are still present and not bent. Usually when
the valve heads are missing or sufficiently bent,
internal engine component debris will be present
to varying degrees in the intake port of the cylinder
head. If this debris is present in ANY of the
cylinder head intake ports, the intake manifold
should be replaced.
This replacement is required due to the complex
inlet runner and plenum configuration of most of
the intake manifolds, making thorough and
complete component cleaning difficult and nearly
impossible to verify the complete removal of
debris. Reinstallation of an intake manifold
removed from an engine with deposits of internal
engine component debris may result in the
ingestion of any remaining debris into the new
Genuine GM Part service engine. This will cause
damage or potential failure of the new Genuine
GM Part service engine long block.

Copyright 2019 General Motors LLC. All Rights Reserved.

Broken Valves, Broken Pistons and
Piston to Cylinder Head Damage –
Catalytic Converter Failures
Broken Valves, Broken Pistons and Piston to
Cylinder Head Damage
Broken valves, broken pistons and piston to cylinder
head damage all create material debris that scatters
throughout the induction system.
⇒ If ANY of the above were to occur, the intake
manifold MUST be replaced and the catalytic
converters must be inspected or subsequent
severe engine damage will occur. This replacement
is required due to the complex inlet runner and
plenum configuration of most of the intake
manifolds, making thorough and complete
component cleaning difficult and impossible to
verify the complete removal of all debris.
Catalytic Converter Failures
When catalytic converter failures occur and the inner
brick becomes plugged and breaks apart, the catalytic
converter material or metal left from the engine can be
sucked back into the engine during valve overlap and
transfer throughout the intake manifold and into the
cylinder. Any such material transfer can cause heavy
wear to piston rings and cylinder walls. Misfires and oil
consumption are the by products of ingested catalytic
converter material into the combustion chamber and
cylinder bores.
Certain 2019 and prior General Motors products may
be equipped with a new style of catalytic converter,
technically known as the close-coupled catalytic
converter, providing quick catalyst warm-up, resulting in
lower tail pipe emissions earlier in the vehicle operating
cycle.

Page 2

August, 2019

Bulletin No.: 00-06-01-026M

If an engine breakdown or non-function were to occur
(such as broken intake/exhaust valve or piston), debris
may be deposited in the converter through engine
exhaust ports. If the engine is non-functioning due to a
severe overheat event, damage to the ceramic “brick”
internal to the catalytic converter may occur. This may
result in ceramic debris being drawn into the engine
through the cylinder head exhaust ports.
If a replacement engine is installed in either of these
instances, the replacement engine may fail due to the
debris being introduced into the combustion chambers
when started.
When replacing an engine for a breakdown or
non-function, an inspection of the catalytic converters
and ALL transferred components (such as exhaust/
intake manifolds) should be performed. Any debris
found should be removed. In cases of engine failure
due to severe overheat, dealers should also inspect
each catalytic converter for signs of melting or cracking
of the ceramic “brick.” If damage is observed, the
converter should be replaced.

Typical Intake Manifold Debris Views
After Internal Engine Damage
View of Debris in Aluminum Intake Manifold –
Throttle Body Opening

4246245

Bulletin No.: 00-06-01-026M

August, 2019

Page 3

View of Debris in Aluminum Intake Manifold – Ports
to Cylinder Heads

4247214

View of Debris in Plastic Intake Manifold – Throttle
Body Opening

4246791

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August, 2019

View of Broken Valve that Blew Debris Back into the
Intake from the Combustion Chamber

4565447

View of Intake from GEN 5 V8 that Experienced
Lifter Collapse and/or Broken Valve Spring

4565440

Bulletin No.: 00-06-01-026M

Bulletin No.: 00-06-01-026M

August, 2019

Page 5

Internal View of Plastic Intake Manifold
Lower Half – Plenum and Runner
Complexity
Notice: The plastic intake manifold CANNOT be
disassembled.
Internal View of Plastic Intake Manifold Lower Half –
Plenum and Runner Complexity

4247259

This internal view shows the plenum and runner
complexity and is the reason why the intake
manifold CANNOT be completely cleaned of debris.
1. Intake port to cylinder head opening.
2. Areas where debris can collect.
3. Areas where debris can collect.
4. Areas where debris can collect.

Ultrasonic welding is an industrial technique whereby
high-frequency ultrasonic acoustic vibrations are locally
applied to workpieces, (in this case the plastic intake
manifold) that are being held together under pressure
to create a solid-state weld. It is commonly used for
plastics and for joining dissimilar materials. In
ultrasonic welding, there are no connective bolts, nails,
soldering materials, or adhesives necessary to bind the
materials together.

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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