Service Update
31170 Rear Suspension Shackle Bolt Contacts HVAC Line
Reference Number:
Attention:

Release Date:
Revision:

N16203117

October 2016
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
Chevrolet
GMC

Model
Express
Savana

Model Year
From
To
2015
2016
2015
2016

RPO
C36
C69

Description
Auxiliary Heater
HVAC System Rr-Air Conditioner

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 2015 and 2016 model year Chevrolet Express and GMC Savana vehicles, equipped with HVAC
system rear - air conditioner (RPO C69) or auxiliary heater (RPO C36), may have contact between the
rear leaf spring shackle bolt and rear HVAC coolant lines that may rub through creating a coolant leak.
This leak may cause the engine to overheat, leading to loss of propulsion or loss of HVAC performance.
Replace the shackle bolt. Inspect and, if necessary, replace the auxiliary heater hose.

Parts
Quantity
1
1 (If Req’d)
1 (If Req’d)
1 (If Req’d)
1 (If Req’d)
1 (If Req’d)

Part Name
Rear Spring Rear Bolt
Auxiliary Air Conditioning Evaporator Hose
Auxiliary Air Conditioning Evaporator Hose
Auxiliary Heater Inlet and Outlet Hose
Auxiliary Heater Inlet and Outlet Hose
Engine Coolant

Part No.
11588857
23172815
23172814
20970677
20970676
12346290(US)
10953464
(Canada)

Note: Use the VIN and the GM Electronic Parts Catalog (EPC) to determine which hose to order.
Warranty Information
Labor
Operation

9102597

Description
Replace Rear Spring Rear Bolt
Add: Auxiliary Air Conditioning Evaporator Tube with Auxiliary
Heater Inlet and Outlet Pipe Replacement
Add: To Recover and Recharge R-134a A/C System

Labor
Time
0.4
2.9

Trans.
Type
ZFAT

Net
Item
N/A

0.3

Service Procedure
1.

Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in SI.

2.

Remove the left rear tire. Refer to Tire and Wheel Removal and Installation in SI.

3.

Support the rear axle independently in order to relieve the tension on the leaf springs.

Copyright 2016 General Motors. All Rights Reserved.

Page 1 of 3

Service Update
31170 Rear Suspension Shackle Bolt Contacts HVAC Line

4593753
4.

Remove the spring shackle to leaf spring mounting bolt (1) and DISCARD.

5.

Install a NEW spring shackle to leaf spring mounting bolt.

6.

Tighten the spring shackle to leaf spring mounting nut.
6.1. First Pass: 100 Nm (74 lb ft)
6.2. Final Pass: (210 degrees)

7.

Remove the support.

4593757
Note: If there are any signs of damage to the auxiliary heater hose or evidence of the auxiliary heater hose contacting
the spring shackle to leaf spring mounting bolt, the auxiliary heater hose MUST be replaced.
8.

Inspect the auxiliary heater hose for any signs of damage or evidence of the auxiliary heater hose contacting the
spring shackle to leaf spring mounting bolt.


If there are NOT any signs of damage to the auxiliary heater hose or evidence of the auxiliary heater hose
contacting the spring shackle to leaf spring mounting bolt, no further action is required.



If there are any signs of damage to the auxiliary heater hose or evidence of the auxiliary heater hose contacting
the spring shackle to leaf spring mounting bolt, replace the auxiliary air conditioning evaporator hose or auxiliary
Page 2 of 3

Service Update
31170 Rear Suspension Shackle Bolt Contacts HVAC Line
heater inlet and outlet hose depending on vehicle content. Refer to Auxiliary Air Conditioning Evaporator Hose
Replacement (Rear) in SI.
9.

Install the left rear tire. Refer to Tire and Wheel Removal and Installation in SI.

10. Lower the vehicle. Refer to Lifting and Jacking the Vehicle in SI.
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.

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 3 of 3

GLOBAL SAFETY FIELD INVESTIGATIONS
DCS4220
URGENT - DISTRIBUTE IMMEDIATELY
Date:

October 17, 2016

Subject: 31170 - Service Update
Rear Suspension Shackle Bolt Contacts HVAC Line
Models: 2015-2016 Chevrolet Express
2015-2016 GMC Savana
Equipped with Auxiliary Heater (RPO C36) or HVAC System Rear-Air
Conditioner (RPO C69)
To:

All Chevrolet and GMC Dealers

General Motors is releasing Service Update 31170 today. The total number of
U.S. vehicles involved is approximately 23,577. Please see the attached
bulletin for details.
Global Warranty Management (GWM)
The Investigate Vehicle History (IVH) screen in the GWM system will be updated
October 18, 2016. A list of involved vehicles in dealer new inventory is attached to this
message. Please hold all warranty transactions until the VIN appears in IVH.
END OF MESSAGE
GLOBAL SAFETY FIELD INVESTIGATIONS