GLOBAL SAFETY FIELD INVESTIGATIONS
DCS6010
URGENT - DISTRIBUTE IMMEDIATELY
Date:

December 17, 2021

Subject: N212346580 - Customer Satisfaction Program
Block Heater Restore
Models: 2017 – 2019 Chevrolet Silverado 2500/3500
2017 – 2019 GMC Sierra 2500/3500
Equipped with 6.6L, 8-cylinder diesel engine (RPO L5P)
To:

All General Motors Dealers

General Motors is releasing Customer Satisfaction Program N212346580
today. The total number of U.S. vehicles involved is approximately 8,258.
Please see the attached bulletin for details.
Important: An initial supply of part 12724955 (HEATER ASM-ENG COOL)
and 85590391 (CORD ASM-ENG COOL HTR) will be pre-shipped in a Fair
Share Allocation based on all impacted VINS of the Dealers registered in
Canada and the following states: Alaska, Colorado, Idaho, Maine, Michigan,
Minnesota, Montana, New York, North Dakota, New Hampshire, South
Dakota, Vermont, Wisconsin, Wyoming. This pre-shipment starts the week of
12/20/21 and will continue for several weeks. Additional States will be added
as GM finishes shipping to Canada and cold weather states and more parts
become available. Pre-shipped parts will be charged to dealer's open parts
account. All orders placed prior to and during the pre-ship will be cancelled. A
quantity limiter may be in effect.
Customer Letter Mailing
The customer letter mailing will be in the near future.
Global Warranty Management (GWM)
The Required Field Action section on the Investigate Vehicle History (IVH) screen will
be updated December 17, 2021. Please hold all warranty transactions until IVH has
been updated.
END OF MESSAGE
GLOBAL SAFETY FIELD INVESTIGATIONS

Customer Satisfaction Program
N212346580 Block Heater Restore
Release Date:
Attention:

December 2021

Revision:

00

The pre-shipped parts are being sent to dealers in the following northern/cold weather areas: Alaska,
Colorado, Idaho, Maine, Michigan, Minnesota, Montana, North Dakota, New Hampshire, New York,
South Dakota, Vermont, Wisconsin, Wyoming and Canada.
This program is in effect until December 31, 2023.

Make
Chevrolet
GMC

Model
Silverado 2500/3500
Sierra 2500/3500

Model Year
From
To

RPO

Description

2017

L5P

6.6L, 8-cylinder diesel engine

2019

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

Correction

Certain 2017-2019 model year Chevrolet Silverado 2500/3500 and GMC Sierra 2500/3500 vehicles
equipped with the Duramax diesel 6.6 liter engine and the optional engine-block heater cord, may have
a condition in which the block heater cable function was disabled.
Dealers will replace the engine block heater and cord.

Parts
Quantity
1
1
2

4

Part Name

Part No.
12724955
85590391
12346290 US
10953464
Canada
Obtain locally
in compliance
w/ GM spec
GMW3420
and Material
Specification
9985809 (all
other
countries)
NPN

Engine Coolant Heater
Power Cord – Engine Coolant Heater
Dex-Cool Engine Coolant

Locally Sourced Automotive Quality Wire Tie

Important: An initial supply of part 12724955 (HEATER ASM-ENG COOL) and 85590391 (CORD ASM-ENG COOL
HTR) will be pre-shipped in a Fair Share Allocation based on all impacted VINS of the Dealers registered in Canada
and the following states: Alaska, Colorado, Idaho, Maine, Michigan, Minnesota, Montana, New York, North Dakota, New
Hampshire, South Dakota, Vermont, Wisconsin, Wyoming. This pre-shipment starts the week of 12/20/21 and will
continue for several weeks. Additional States will be added as GM finishes shipping to Canada and cold weather states
and more parts become available. Pre-shipped parts will be charged to dealer's open parts account. All orders placed
prior to and during the pre-ship will be cancelled. A quantity limiter may be in effect.
Note: The per gallon part number for coolant is listed in the part table. If your facility buys the correct coolant in a bulk
quantity, do not order the gallon units.
Warranty Information
Labor
Operation
9106097
9106098

9106099

Description
Install Revised Engine Coolant Heater Element and Cord
Customer Reimbursement Approved
- For USA and Canada dealers only
- For Export dealers only
Customer Reimbursement Denied – For USA dealers only

Labor
Time
1.5
N/A
0.2
N/A

Trans.
Type
ZFAT
ZFAT

Net
Item
N/A
*

ZFAT

**

Note: To avoid having to “H” route the customer reimbursement transaction for wholesale approval, it must be submitted
prior to the repair transaction.
Copyright 2021 General Motors. All Rights Reserved.

Page 1 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore
* For USA and Canada: Submit the dollar amount reimbursed to the customer in Net/Reimbursement. Submit $20.00
USD ($25.00 CAN) administrative allowance in Net/Admin Allowance.
For Export: Submit the dollar amount reimbursed to the customer in Net/Reimbursement.
** Submit $10.00 administrative allowance in Net/Admin Allowance.
Service Procedure
DANGER: When performing the following repairs, ensure the engine and coolant are at room temperature. When
removing the engine block heater, the coolant in the engine will drain out. This coolant may injure the technician if the
coolant is hot.
Note: It is critical that the radiator surge tank is topped off with an additional 1.6 L (2 qt) of coolant to fill the upper and
lower radiator surge tank chambers. If the coolant tank is not purged and filled properly, there will be air pockets in the
coolant tank which will require the customer to return to the dealership to address low coolant warning.
1.

Remove the new service engine heater power cord from the box and uncoil the cord.

2.

Lower the engine heater element end of the new power cord to the underside of the vehicle.

5946406

•

Start lowering the cord inboard of the battery toward the front of dash.

5946404

•

It should come out in the area identified above.

Page 2 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore
3.

Raise the vehicle and remove the right front wheel. Refer to Tire and Wheel Removal and Installation (8-Lug Wheel)
in SI.

4.

Remove the right front wheelhouse liner. Refer to Front Wheelhouse Liner Replacement - Right Side in SI.

5.

Looking through the area between the frame and suspension, locate the engine block heater.

Note: It is not necessary to drain the radiator. The engine block coolant will be drained when the engine coolant heater
is removed.

5420812

Note: The removal of the old coolant heater element requires a 30mm Socket wrench. The installation of the new coolant
heater element requires a 26mm socket wrench.
6.

Place a large drain pan under the vehicle to capture the coolant. Remove the engine coolant heater. Refer to Engine
Coolant Heater Replacement (L5P) in SI.

7.

After removing the original block heater, take care to remove the old cured thread sealant in the block. Failure to
remove the old thread sealant will result in cross threading or binding of the replacement block heater.

Caution: Do not under torque the engine coolant heater. This can result in a coolant leak. A torque wrench, with tactile
or audible feedback when torque has been achieved, should be used. Tighten to 90 N.m. (66 lb ft). DO NOT
OVERTIGHTEN. Hand start the block heater carefully and secure at least 3 full turns before further tightening with a
socket wrench.
Note: The new engine block heater element has the thread sealer applied at the time of manufacture. DO NOT INSTALL
ADDITIONAL SEALER to the threads.

5946408

Page 3 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore
8.
9.

Hand start the block heater carefully and secure at least 3 full turns before further tightening with a socket wrench.
Tighten to 90 N.m. (66 lb ft). DO NOT OVERTIGHTEN. A torque wrench, with tactile or audible feedback when torque
has been achieved, should be used.

5946410

10. Slide the new power cord forward in the vehicle, toward the coolant heater element. Place the power cord
connector near the coolant heater element. DO NOT CONNECT the power cord to the heater element at this time,
it will be connected after the cooling system pressure test.

5495375

11. Route the new engine coolant heater power cord (shown in red) to the upper motor compartment. Begin at the
Element (1) and secure the wire tie (2) around the negative battery cable (black) and the engine chassis harness
(grey).
12. Lower the vehicle.

Page 4 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore

5495378

13. Route the power cord (shown in red) as shown and secure to the surge tank hose (blue) with a wire tie.

Engine Compartment Routing Overview

5946413

Push pin attachments (3), wire tie attachments (4).

5420816

Page 5 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore
14. Position the power cord along the inner fender and secure to the existing hole using the first (closest to the heater
element) push pin wire tie attached to the harness.

5420817

15. Secure the power cord to the fender flange with a wire tie as shown. Some vehicles may have a hood seal or
headlamp attachment at this location. Position the wire tie under the seal/bracket.

5420818

16. Locate the drill location on the front compartment front sight shield. Mark the location.

Page 6 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore

5420819

17. Drill a 5mm (13/64 in.) hole in the marked area. Use care to not damage components below the drill location.
18. Route the power cord from the fender flange area under the front compartment front sight shield.

5420820

19. Create a gentle bend in the power cord and place the power cord plug over the hole in the site shield. Ensure the
prongs on the power cord plug are facing toward the right fender.

5420823

Page 7 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore
20. Secure the power cord plug to the to the front compartment front sight shield with a wire tie as shown. Ensure the
prongs are facing toward the right front fender.

5420824

21. Locate the hole on the passenger side upper tie bar bracket.

5420825

22. Position the harness up under the front compartment front sight shield and secure it using the second (closest to the
electrical plug) push pin wire tie on the harness.
23. Trim all wire ties as necessary.
Important: The Vac-N-Fill Procedure must be used when refilling the cooling system. If the Vac-N-Fill Procedure is not
used, the customer will return to the dealership with a low coolant condition.
24. Fill the cooling system. Refer to Cooling System Draining and Filling (Vac N Fill) in SI.
25. Pressurize the cooling system. Refer to Cooling System Leak Testing (L5P) in SI.
26. Partially raise the vehicle and inspect the new engine block heater for coolant leaks.
•

Inspect the interface between the engine block heater and the engine block (threaded area) for leaks.

•

Check the cavity where the electrical connector fits for leaks.

27. Plug the new engine coolant heater cord assembly into the heater and secure it with the metal clip.
28. Reinstall the right front wheelhouse liner. Refer to Front Wheelhouse Liner Replacement - Right Side in SI.
29. Reinstall the right front wheel and tire. Refer to Tire and Wheel Removal and Installation (8-Lug Wheel) in SI.
Page 8 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore
30. Remove the leak testing equipment from the surge tank.

5443211

31. Open the lower radiator surge tank cap (1) a ¼ of a turn counterclockwise.

5443213

32. Using a funnel, slowly fill the radiator surge tank with 1.6 L (2 qt) of coolant to fill the lower radiator surge tank
chamber. The overflow tube will flow to the left and down as shown above, and slowly move to the lower radiator
surge tank chamber.

5443214

33. When completed, the radiator surge tank should be filled as shown above (a).
Note: Be sure the lower radiator surge tank cap is completely closed and locked in place to avoid getting air into the
cooling system after filling. There will be a snap sound when the cap is completely closed and locked in place.
Page 9 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore

5443215

34. Close the lower radiator surge tank cap (1) clockwise.

5443214

35. If the coolant level is below the fill neck level shown (a) add coolant to the fill neck level shown.
36. Install radiator surge tank cap by turning counterclockwise.
37. Rinse away any excess coolant from the engine and the engine compartment.
38. Perform the following check list before delivering the vehicle to the customer:
•
•
•
•
•

Drain/fill/burp coolant system with vac/fill equipment.
Cord attached with 4 tie straps.
Cord attached with 2 push pin wire ties.
Engine block heater torqued to 90 N.m. (66 lb ft).
Cord properly connected to heater with metal clip engaged.

Dealer Responsibility
All new, used, GM Certified Used, courtesy transportation vehicles, dealer shuttle vehicles, etc. in dealers' possession
and subject to this program 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, dealertraded, 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.
Dealers are to service all vehicles subject to this program at no charge to customers, regardless of mileage, age of vehicle,
or ownership, through December 31, 2023. Customers who have recently purchased vehicles sold from your vehicle
Page 10 of 11

Customer Satisfaction Program
N212346580 Block Heater Restore
inventory, and for which there is no customer information indicated on the involved vehicle listing, are to be contacted by
the dealer. Arrangements are to be made to make the required correction according to the instructions contained in this
bulletin. Program follow-up cards should not be used for this purpose, since the customer may not as yet have received
the notification letter.
In summary, whenever a vehicle subject to this program enters your vehicle inventory or is in your facility for service
through December 31, 2023, you must take the steps necessary to be sure the program correction has been made before
selling or releasing the vehicle.
Dealer Reports
For dealers with involved vehicles, a listing has been prepared and will be available through GM GlobalConnect Maxis
Field Action Reports or sent directly to export dealers. The Inventory tab of the dealer reports will contain VINs that
apply to this field action. This information is intended to assist dealers with the PROMPT COMPLETION of these
vehicles. The Customer In-Service tab will contain customer names and addresses from Motor Vehicle Registration
Records. The use of such motor vehicle registration data for any purpose other than follow-up necessary to complete
this field action may be a violation of law in several states.
Courtesy Transportation – For USA & Canada
Courtesy transportation is available for customers whose vehicles are involved in a product program and still within the
warranty coverage period. See General Motors Service Policies and Procedures Manual for courtesy transportation
program details.
Customer Reimbursement
Customer requests for reimbursement of previously paid repairs to correct the condition described in this bulletin are to
be submitted to the dealer prior to or by December 31, 2022. See General Motors Service Policies and Procedures
Manual, Section 6.1.11 – Product Field Action Customer Reimbursement Procedure (USA & Canada) or local Policies
and Procedures, for details.

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

Page 11 of 11