20NA029

Bulletin No.:
Service Bulletin
Date:
20-NA-029
February, 2020
TECHNICAL
Subject:
Ticking, Tap, or Rattle Noise from Engine
This bulletin replaces PIP5331H. Please discard PIP5331H.
Brand:
Buick
Cadillac
Chevrolet
GMC
Model:
Model Year:
VIN:
from
to
from
to
Engine:
(3.6L)
Enclave
2013
2020
LFY, LLT
LaCrosse
2013
2017
LFX
ATS
2013
2019
LFX, LF4
CTS
2013
2019
LFX, LF3
SRX
2013
2016
LFX
XTS
2013
2019
LFX, LF3
Camaro
2013
2015
LFX
Colorado
2015
2016
LFX
Captiva Sport
(VIN L)
2013
2015
LFX
Captiva
2016
2016
LFX
Equinox
2013
2017
LFX
Impala
Models
2013
2020
LFX
Traverse
2013
2020
LFY, LLT
Acadia
2013
2017
LLT
Terrain
2013
2017
LFX
Canyon
2015
2016
LFX
Transmission:
Involved Region or Country
North America, Europe, Russia, Middle East, Iraq, Israel, Palestine, Argentina, Brazil,
Bolivia, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay, Venezuela, Japan, Cadillac
Korea (South Korea), GM Korea Company, China, Taiwan, Thailand, Singapore,
Philippines, Egypt, Other Africa, South Africa
Condition
Some customers may comment on one or more of the following noises from the vehicle:
• Rattle
• Tick
• Knock
Important Information
Prior to any diagnosis, please check the oil level ensuring it is full, and ensure there is
sufficient oil pressure available in the engine.
If there are any drivability concerns, they should be addressed prior to the following
diagnostic progression.
Please take a sound file or video with sound of the noise prior to dis-assembly.
Copyright 2020 General Motors LLC. All Rights Reserved.
Page 2
February, 2020
Bulletin No.: 20-NA-029
Service Procedure
1. Perform injector diagnosis to ensure there are no
leaking injectors causing a noise due to excessive
fuel in 1 cylinder.
1.1. Perform GDS2 or AFIT test on injectors to
isolate a leaking injector.
1.2. Replace any out of specification injectors.
1.3. Re-evaluate the noise.
2. Remove the intake manifold and visually inspect
for excessive carbon on the intake valve stems and
top of the valve causing noise.
2.1. If carbon is present, then follow the latest
version of Service Bulletin 16-NA-383 to
clean the valves or replace heads as needed.
2.2. Re-evaluate the noise concern.
4480610
4475559
3. Remove the cam cover of the affected bank (both if
needed) for inspection of the SHLA (1) (Stationary
Hydraulic Lash Adjusters) (Lifters).
4. Push down on the rocker end at the SHLA to test
for a soft or spongy feel.
Note: Right side exhaust are most common.
4.1. If soft or spongy SHLAS are found, carefully
remove the affected head and inspect the oil
passage (1) below the head gasket for debris.
4.2. If debris is found, inspect the camshaft caps
for wear or discoloration due to lack of oil.
4.3. If wear or discoloration is found, then replace
the cylinder head assembly with camshafts.
4.4. If there is no wear or discoloration, clean the
oil passages and replace the head gasket.
4.5. Change the oil and filter.
4.6. Re-evaluate the noise concern.
5. Raise the vehicle while running or with an assistant
inside.
6. With chassis ears or a stethoscope, listen to the
right and left side of the engine.
7. Once the noise is isolated or if unable to isolate,
remove the piston and rod assemblies from the
affected bank(s) to inspect for either;
• Loose rod bushing in the rod.
• Loose wrist pin in the bushing.
– There should be no metal through the oil for this
condition.
– If this metal found, a piston and rod assembly will
repair this noise.
For all of the above engine repairs, engine replacement
is not necessary. Please perform the repairs for these
conditions.
Note: If metal is found in the oil or throughout the
system, refer to the latest version of Service Bulletin
19-NA-256.
Once all of the above inspections and/or diagnostics
are completed, If nothing is found to be the cause for
the noise, engine replacement MAY be necessary.
Bulletin No.: 20-NA-029
February, 2020
Page 3
Parts Information
Use the vehicle identification number (VIN) and refer to
the GM Electronic Parts Catalog (EPC) to determine
the proper part(s) to order.
Warranty Information
For Vehicles Repaired Under Powertrain Warranty, Use
the Appropriate Labor Operation For Process
Performed.
Please review IVH for warranty information.
Version
1
Modified
Released February 7, 2020
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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