GLOBAL SAFETY FIELD INVESTIGATIONS
DCS5619
URGENT - DISTRIBUTE IMMEDIATELY
Date:

December 21, 2020

Subject: N202321920 - Service Update
Engine Coolant Inlet Pipe
Models: 2021 Cadillac XT4 and XT5
2021 Chevrolet Trailblazer
2021 GMC Acadia
To:

All General Motors Dealers

General Motors is releasing Service Update N202321920 today. The total
number of U.S. vehicles involved is approximately 12. Please see the
attached bulletin for details.
Global Warranty Management (GWM)
The Required Field Action section on the Investigate Vehicle History (IVH) screen will
be updated December 22, 2020 or sooner. A list of involved vehicles in dealer new
inventory is attached to this message. Please hold all warranty transactions until IVH
has been updated.
END OF MESSAGE
GLOBAL SAFETY FIELD INVESTIGATIONS

Service Update
N202321920 Engine Coolant Inlet Pipe
Release Date:
Attention:

December 2020

Revision:

00

This service update includes vehicles in dealer inventory and customer vehicles that return to the
dealership for any reason. This bulletin will expire at the end of the involved vehicle’s New Vehicle Limited
Warranty period.

Make
Cadillac
Cadillac
Chevrolet
GMC

Model
XT4
XT5
Blazer
Acadia

Model Year
From
To
2021

RPO

Description

2021

Involved vehicles are marked “open” on the Investigate Vehicle History screen in GM Global Warranty Management
system. This site should always be checked to confirm vehicle involvement prior to beginning any required inspections
and/or repairs.
Condition

A small number of 2021 model year Cadillac XT4 and XT5, Chevrolet Blazer and GMC Acadia vehicles
may have a coolant inlet pipe that may present an obstructed threaded hole for the coolant temp sensor
which could result in the check engine light coming on or a potential coolant leak.
Dealers are to replace the coolant inlet pipe and temperature sensor.

Correction
Parts
Quantity
1
1
1
1

Part Name
Engine Coolant Thermostat Inlet Pipe
Engine Coolant Temperature Sensor
Gasket, Thermostat Inlet Pipe
Engine Coolant

1
1
2

Part No.
55507975
55488246
55504553
12378390
US
10953456
CA
11603519
55502444
22816982

Exhaust Pipe Clamp
Catalytic Converter Gasket
Exhaust Muffler Gasket

It is estimated that there are only 15 involved vehicles that will require parts being replaced. Due to the small number
of vehicles anticipated that will need this repair and the limited initial parts availability, dealers are encouraged
not to order these parts for use as shelf stock.
Reminder: Parts may be removed from Retail Inventory Management (RIM). Dealers should review the affected parts
to confirm RIM managed status. Parts may have quantity limiters in effect.
Warranty Information
Labor
Operation
9105491
9105492

Description
Inspect Only – No Further Action Required
Repair (includes inspection)
Acadia
Blazer
XT5
XT4
XT4 (AWD)

Labor
Time
0.6

Trans.
Type
ZFAT
ZFAT

Net
Item
N/A
N/A

2.5
2.2
2.1
2.2
2.4

Service Procedure
1.

2.

Perform a cooling system leak check per Coolant System Leak Testing in SI.
•

If the cooling system maintains the rated pressure for at least 2 minutes, no further action is required.

•

If the cooling system does not maintain the rated pressure for at least two minutes, proceed to step 2.

Locate the coolant temperature sensor in the engine coolant thermostat housing inlet pipe at the front of the engine.

Copyright 2020 General Motors. All Rights Reserved.

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Service Update
N202321920 Engine Coolant Inlet Pipe
3.

Pressurize the cooling system again with the EN-24460-A Cooling System Pressure Tester per Coolant System
Leak Testing in SI and observe the coolant temperature sensor to see if it is leaking.
•

If the coolant temperature sensor IS leaking, replace the Engine Coolant Thermostat Housing Inlet Pipe.
Refer to Engine Coolant Thermostat Housing Inlet Pipe Replacement (LSY) in SI.

•

If the coolant temperature sensor is NOT leaking, perform further diagnosis and/or repairs under
warranty on a separate line. No further action is covered by this field action.

Dealer Responsibility
Whenever a vehicle subject to this service update enters your vehicle inventory or is in your facility for service in the
future, and the vehicle is still covered under the New Vehicle Limited Warranty, you must take the steps necessary to be
sure the service update correction has been made before selling or releasing the vehicle.
All new, used, GM Certified Used, courtesy transportation vehicles, dealer shuttle vehicles, etc. in dealers' possession
and subject to this bulletin must be held and inspected/repaired per the service procedure of this bulletin before customers
take possession of these vehicles. Involved vehicles must be held and not delivered to customers, dealer-traded,
released to auction, used for demonstration, or any other purpose.
All GM Certified Used vehicles currently in the dealers’ inventory within the Certified Pre-Owned Inventory System
(CPOIS) will be de-certified and must be held and remedied per the service procedure in this bulletin. Upon submitting
an accepted/paid warranty transaction in the Global Warranty Management (GWM) system, the vehicle can be re-certified
for sale within the CPOIS system, or once again be used in the CTP program.
Dealer Reports
The Inventory tab of the Open Vehicle Report will contain Service Update Bulletin VINs that apply to this field action.
This information is intended to assist dealers with the PROMPT COMPLETION of these vehicles. The Customer InService tab will not contain Service Update Bulletin VIN data because the intent of a Service Update Bulletin is to not
inconvenience a customer with a special trip for service. Service Update Bulletins are to be completed when the
customer is in for a regularly scheduled visit.

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 tools, equipment, 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 dealer for information on whether your
vehicle may benefit from the information.

We Support
Voluntary Technician
Certification

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