21-NA-118

Service Bulletin
Bulletin No.:
21-NA-118
Date:
June, 2023
TECHNICAL
Subject:
Vibration Type Noise Heard at Highway Speeds or with Engine Speed at
1,300-1,500 RPM
This Bulletin replaces PIT5825. Please Discard PIT5825.
Brand:
Cadillac
Model:
Model Year:
VIN:
from
to
from
to
2020
2023
-
-
Engine:
Transmission:
LGX
All
XT5
XT6
Chevrolet
Blazer
GMC
Acadia
Involved Region or Country
North America, Middle East
Condition
Some customers may comment on a vibration type noise at highway speeds or with
Engine Speed at 1,300-1,500 RPM heard under the vehicle.
Cause
The cause of the condition may be some of the metal gasket tabs between the front
exhaust and muffler are not fully crimped, exhibiting some spring-back, allowing for them
to touch at certain speeds / RPMs.
Correction
If you encounter a vehicle with the above concern, complete the following procedure
below.
Service Procedure
Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between
the procedures set forth in this bulletin and the
laws that apply to your dealership, you must follow
those applicable laws.
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.
5776432
Copyright 2023 General Motors LLC. All Rights Reserved.
Page 2
June, 2023
Bulletin No.: 21-NA-118
Labor Operation
Description
Labor Time
4050272
Exhaust System Alignment
Use Published Labor
Operation Time
Parts Information
No parts are required for this repair.
Warranty Information
For vehicles repaired under warranty, use:
Version
3
Modified
Released March 19, 2021
Revised August 10, 2021 —Added 2019 Model Year XT5, Blazer and Acadia. Added PIT
supersession statement.
Released June 08, 2023 — Added 2023 Model Year.
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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