21NA118

Service Bulletin
Bulletin No.:
21-NA-118
Date:
May, 2021
TECHNICAL
Subject:
Vibration Type Noise Heard at Highway Speeds or with Engine Speed at
1,300-1,500 RPM
Brand:
Model:
Cadillac
XT5
XT6
Chevrolet
Blazer
GMC
Acadia
Model Year:
VIN:
from
to
2020
2021
from
to
Engine:
Transmission:
LGX
All
Involved Region or Country
North America, Russia, Middle East, Israel, Palestine, Chile, Columbia, Ecuador, Peru,
Japan, S. Korea, Australia and New Zealand.
Condition
Some customers may comment on a vibration type noise at highway speeds and/or with
Engine Speed at 1,300-1,500 RPM. The sound can usually be heard from under the
vehicle.
Cause
The cause of the condition may be due to some of the metal gasket tabs between the
front exhaust and muffler not being fully crimped, exhibiting some spring-back, allowing
for them to touch at certain speeds / RPMs.
Correction
Refer to the procedure below to correct the condition stated above.
With a small punch or chisel and hammer bend/crimp
the tabs on the exhaust gasket in further to prevent any
spring-back and provide increased clearance between
the two tabs to correct the noise or cutting the tabs off
the gaskets is also acceptable.
Service Procedure
Parts Information
No parts are required for this repair.
5776432
Copyright 2021 General Motors LLC. All Rights Reserved.
Page 2
May, 2021
Bulletin No.: 21-NA-118
Warranty Information
For vehicles repaired under the Bumper-to-Bumper
coverage (Canada Base Warranty coverage), use the
following labor operation. Reference the Applicable
Warranties section of Investigate Vehicle History (IVH)
for coverage information.
Labor Operation
Description
Labor Time
4088058*
Align Exhaust System
0.3 hr
*This is a unique Labor Operation for Bulletin use only.
Version
1
Modified
Released March 19, 2021
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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