
Black plate (22,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-22 Vehicle Care
3. Fill the coolant surge tank withthe proper mixture to the FULL
COLD mark.
4. With the coolant surge tank pressure cap off, start the
engine and let it run until the
engine coolant temperature
gauge indicates approximately
90°C (195°F).
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper mixture to the coolant surge tank
until the level reaches the FULL
COLD mark.
5. Replace the pressure cap. Be sure the pressure cap is
hand-tight and fully seated.
6. Verify coolant level after the engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1 through 6.
Notice: If the pressure cap is not
tightly installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
Engine Overheating
If the vehicle has the Duramax®
Diesel engine, see the Duramax
Diesel Supplement for more
information.
The vehicle has several indicators
to warn of engine overheating. There is a coolant temperature
gauge on the vehicle's instrument
panel. See
Engine Coolant
Temperature Gauge on page 5‑16.
In addition, there are ENGINE
OVERHEATED STOP ENGINE,
ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS
REDUCED messages in the Driver
Information Center (DIC) on the
instrument panel. See Engine
Cooling System Messages on
page 5‑41 andEngine Power
Messages on page 5‑42.
If the decision is made not to lift the
hood when this warning appears,
get service help right away. See
Roadside Assistance Program (U.S.
and Canada) on page 13‑7 or
Roadside Assistance Program
(Mexico) on page 13‑9.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.

Black plate (23,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-23
Then check to see if the engine
cooling fans are running. If the
engine is overheating, both fans
should be running. If they are not,
do not continue to run the engine
and have the vehicle serviced.
Notice:Engine damage from
running your engine without
coolant is not covered by the
vehicle warranty. See Overheated
Engine Protection Operating
Mode for information on driving
to a safe place in an emergency.
Notice: If the engine catches fire
while driving with no coolant, the
vehicle can be badly damaged.
The costly repairs would not be
covered by the vehicle warranty.
See Overheated Engine
Protection Operating Mode on
page 10‑24 for information on
driving to a safe place in an
emergency.If Steam is Coming from the
Engine Compartment
{WARNING
Steam from an overheated engine
can burn you badly, even if you
just open the hood. Stay away
from the engine if you see or hear
steam coming from it. Turn it off
and get everyone away from the
vehicle until it cools down. Wait
until there is no sign of steam or
coolant before you open
the hood.
If you keep driving when the
vehicles engine is overheated,
the liquids in it can catch fire. You
or others could be badly burned.
Stop the engine if it overheats,
and get out of the vehicle until the
engine is cool.
(Continued)
WARNING (Continued)
SeeOverheated Engine
Protection Operating Mode on
page 10‑24 for information on
driving to a safe place in an
emergency.
If No Steam is Coming from
the Engine Compartment
The ENGINE OVERHEATED
STOP ENGINE or the ENGINE
OVERHEATED IDLE ENGINE
message, along with a low coolant
condition, can indicate a serious
problem.
If there is an engine overheat
warning, but no steam is seen or
heard, the problem may not be too
serious. Sometimes the engine can
get a little too hot when the vehicle:
.Climbs a long hill on a hot day
.Stops after high-speed driving

Black plate (24,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-24 Vehicle Care
.Idles for long periods in traffic
.Tows a trailer; seeTrailer Towing
on page 9‑78.
If the ENGINE OVERHEATED
STOP ENGINE or the ENGINE
OVERHEATED IDLE ENGINE
message appears with no sign of
steam, try this for a minute or so:
1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest
fan speed. Open the windows as
necessary.
3. If stopped in a traffic jam, apply the brake, shift to N (Neutral);
otherwise, shift to the highest
gear while driving —D (Drive)
or 3 (Third).
If the temperature overheat gauge
is no longer in the overheat zone or
an overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slowly
for about 10 minutes. Keep a safe vehicle distance from the vehicle in
front. If the warning does not come
back on, continue to drive normally.
If the warning continues, pull
over, stop, and park the vehicle
right away.
If there is no sign of steam, idle
the engine for five minutes while
parked. If the warning is still
displayed, turn off the engine
until it cools down. Also, see
“Overheated Engine Protection
Operating Mode”
later in this
section.
Overheated Engine
Protection
Operating Mode
If an overheated engine condition
exists and the ENGINE POWER IS
REDUCED message displays, an
overheat protection mode which
alternates firing groups of cylinders
helps to prevent engine damage.
In this mode, a loss in power and
engine performance will be noticed. This operating mode allows the
vehicle to be driven to a safe
place in an emergency. Driving
extended km (mi) and/or towing a
trailer in the overheat protection
mode should be avoided.
Notice:
After driving in the
overheated engine protection
operating mode, to avoid engine
damage, allow the engine to cool
before attempting any repair.
The engine oil will be severely
degraded. Repair the cause of
coolant loss, change the oil and
reset the oil life system. See
Engine Oil on page 10‑7.
Engine Fan
If the vehicle has a clutched engine
cooling fan, when the clutch is
engaged, the fan spins faster to
provide more air to cool the engine.
In most everyday driving conditions,
the fan is spinning slower and the
clutch is not fully engaged. This
improves fuel economy and reduces
fan noise. Under heavy vehicle

Black plate (26,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-26 Vehicle Care
What to Use
To determine what kind of fluid to
use, seeRecommended Fluids and
Lubricants on page 11‑12. Always
use the proper fluid.
Notice: Use of the incorrect fluid
may damage the vehicle and the
damages may not be covered by
the vehicle's warranty. Always
use the correct fluid listed in
Recommended Fluids and
Lubricants on page 11‑12.
Washer Fluid
What to Use
When windshield washer fluid needs
to be added, be sure to read the
manufacturer's instructions before
use. Use a fluid that has sufficient
protection against freezing in an
area where the temperature may fall
below freezing.
Adding Washer Fluid
The vehicle has a low washer fluid
message on the DIC that comes
on when the washer fluid is low.
The message is displayed for
15 seconds at the start of each
ignition cycle. When the WASHER
FLUID LOW ADD FLUID message
displays, washer fluid will need to
be added to the windshield washer
fluid reservoir.
Open the cap with the washer
symbol on it. Add washer fluid until
the tank is full. See Engine
Compartment Overview on
page 10‑6 for reservoir location. Notice
.When using concentrated
washer fluid, follow the
manufacturer's instructions
for adding water.
.Do not mix water with
ready-to-use washer fluid.
Water can cause the solution
to freeze and damage the
washer fluid tank and other
parts of the washer system.
.Fill the washer fluid tank only
three-quarters full when it is
very cold. This allows for
fluid expansion if freezing
occurs, which could
damage the tank if it is
completely full.
.Do not use engine coolant
(antifreeze) in the windshield
washer. It can damage the
windshield washer system
and paint.

Black plate (3,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Service and Maintenance 11-3
Maintenance
Schedule
Owner Checks and Services
At Each Fuel Stop
.Check the engine oil level. See
Engine Oil on page 10‑7.
Once a Month
.Check the tire inflation
pressures. See Tire Pressure on
page 10‑58.
.Inspect the tires for wear. See
Tire Inspection on page 10‑65.
.Check the windshield washer
fluid level. See Washer Fluid on
page 10‑26.
Engine Oil Change
When the CHANGE ENGINE OIL
SOON message displays, have the
engine oil and filter changed within
the next 1 000 km/600 mi. If driven
under the best conditions, the
engine oil life system might not
indicate the need for vehicle service for more than a year. The engine oil
and filter must be changed at least
once a year and the oil life system
must be reset. Your trained dealer
technician can perform this work.
If the engine oil life system is reset
accidentally, service the vehicle
within 5 000 km/3,000 mi since
the last service. Reset the oil life
system when the oil is changed.
See
Engine Oil Life System on
page 10‑10.
Tire Rotation and Required
Services Every 12 000 km/
7,500 mi
Rotate the tires, if recommended
for the vehicle, and perform the
following services. See Tire
Rotation on page 10‑65.
.Check engine oil level and oil
life percentage. If needed,
change engine oil and filter, and
reset oil life system. See Engine
Oil on page 10‑7 andEngine Oil
Life System on page 10‑10.
.Check engine coolant level. See
Engine Coolant on page 10‑19.
.Check windshield washer fluid
level. See Washer Fluid on
page 10‑26.
.Visually inspect windshield
wiper blades for wear, cracking,
or contamination. See Exterior
Care on page 10‑98. Replace
worn or damaged wiper blades.
See Wiper Blade Replacement
on page 10‑36.
.Check tire inflation pressures.
See Tire Pressure on
page 10‑58.
.Inspect tire wear. See Tire
Inspection on page 10‑65.
.Visually check for fluid leaks.
.Inspect engine air cleaner filter.
See Engine Air Cleaner/Filter on
page 10‑17.
.Inspect brake system.

Black plate (12,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
11-12 Service and Maintenance
Recommended Fluids, Lubricants, and Parts
Recommended Fluids and Lubricants
This maintenance section applies to vehicles with a gasoline engine. If the vehicle has a diesel engine and/or an
Allison Transmission, see the maintenance schedule section in the DURAMAX® Diesel supplement.
Fluids and lubricants identified below by name, part number, or specification can be obtained from your dealer.Usage Fluid/Lubricant
Engine Oil Use only engine oil licensed to the dexos1 specfication, or equivalent, of
the proper SAE viscosity grade. ACDelco dexos1 Synthetic Blend is
recommended. See
Engine Oil on page 10‑7.
Engine Coolant 50/50 mixture of clean, drinkable water and use only DEX-COOL coolant.
See
Engine Coolant on page 10‑19.
Hydraulic Brake System DOT 3 Hydraulic Brake Fluid (GM Part No. 12377967, in
Canada 89021320).
Windshield Washer Automotive windshield washer fluid that meets regional freeze protection
requirements.
Power Steering System GM Power Steering Fluid (GM Part No. 89021184, in Canada 89021186).
Automatic Transmission DEXRON®-VI Automatic Transmission Fluid.
Key Lock Cylinders Multi-Purpose Lubricant, Superlube (GM Part No. 12346241, in
Canada 10953474).

Black plate (3,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
INDEX i-3
Carbon MonoxideEngine Exhaust . . . . . . . . . . . . . . . 9-33
Tailgate . . . . . . . . . . . . . . . . . . . . . . . 2-10
Winter Driving . . . . . . . . . . . . . . . . 9-13
Cargo Lamp . . . . . . . . . . . . . . . . . . . . 6-8
Cautions, Danger, and Warnings . . . . . . . . . . . . . . . . . . . . . . . . iv
CD Player . . . . . . . . . . . . . . . . . . . . . 7-15
CD/DVD Player . . . . . . . . . . . . . . . . 7-21
Center Console Storage . . . . . . . . 4-2
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 10-42
Center Seat . . . . . . . . . . . . . . . . . . . . 3-4
Chains, Tire . . . . . . . . . . . . . . . . . . 10-74
Charging System Light . . . . . . . . 5-22
Check Engine Light . . . . . . . . . . . . . . . . . . 5-22
IgnitionTransmission Lock . . . . . . . . 10-35 Child Restraints
Infants and Young
Children . . . . . . . . . . . . . . . . . . . . . 3-41
Lower Anchors and Tethers for Children . . . . . . . . . 3-47
Older Children . . . . . . . . . . . . . . . . 3-39
Securing . . . . . . . . . . . . . . . . 3-55, 3-58
Systems . . . . . . . . . . . . . . . . . . . . . . 3-44
Cigarette Lighter . . . . . . . . . . . . . . . 5-10
Circuit Breakers . . . . . . . . . . . . . . 10-44
Cleaning Exterior Care . . . . . . . . . . . . . . . 10-98
Interior Care . . . . . . . . . . . . . . . 10-101
Climate Control Systems . . . 8-1, 8-4 Air Conditioning . . . . . . . . . . 8-1, 8-4
Dual Automatic . . . . . . . . . . . . . . . . 8-5
Heating . . . . . . . . . . . . . . . . . . . 8-1, 8-4
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Cluster, Instrument . . . . . . . . . . . . 5-12
Collision Damage Repair . . . . . 13-14
Compass . . . . . . . . . . . . . . . . . . . . . . . 5-5
Connections, OnStar
®. . . . . . . . . 14-4 Control of a Vehicle . . . . . . . . . . . . . 9-4
Convex Mirrors . . . . . . . . . . . . . . . . 2-14
Coolant
Engine . . . . . . . . . . . . . . . . . . . . . . 10-19
Engine TemperatureGauge . . . . . . . . . . . . . . . . . . . . . . 5-16
Cooling System . . . . . . . . . . . . . . . 10-18
Engine Messages . . . . . . . . . . . . 5-41
Courtesy Transportation Program . . . . . . . . . . . . . . . . . . . . . 13-13
Cruise Control . . . . . . . . . . . . . . . . . 9-58
Light . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30
Cupholders . . . . . . . . . . . . . . . . . . . . . 4-1
Customer Assistance . . . . . . . . . . 13-6 Offices . . . . . . . . . . . . . . . . . . 13-4, 13-5
Text Telephone (TTY)Users . . . . . . . . . . . . . . . . . . . . . . . 13-6
Customer Information Service PublicationsOrdering Information . . . . . . 13-16
Customer Satisfaction
Procedure . . . . . . . . . . . . . . 13-1, 13-3

Black plate (4,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
i-4 INDEX
D
Damage Repair, Collision . . . . . 13-14
Danger, Warnings, andCautions . . . . . . . . . . . . . . . . . . . . . . . . iv
Data Recorders, Event . . . . . . . 13-19
Daytime Running Lamps (DRL) . . . . . . . . . . . . . . . . . . 6-3
Defensive Driving . . . . . . . . . . . . . . . 9-3
Delayed Locking . . . . . . . . . . . . . . . . 2-8
Devices, Auxiliary . . . . . . . . . . . . . 7-32
Diagnostics, OnStar
®. . . . . . . . . . 14-5
Distracted Driving . . . . . . . . . . . . . . . 9-2
Dome Lamps . . . . . . . . . . . . . . . . . . . 6-8
Door Ajar Messages . . . . . . . . . . . . . . . 5-40
Delayed Locking . . . . . . . . . . . . . . . 2-8
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Power Locks . . . . . . . . . . . . . . . . . . . 2-8
Rear Doors . . . . . . . . . . . . . . . . . . . . 2-9
Drive Belt Routing, Engine . . . . . 12-6
Driver Information
Center (DIC) . . . . . . . . . . . . . . . . . 5-30 Driving
Characteristics and
Towing Tips . . . . . . . . . . . . . . . . . 9-74
Defensive . . . . . . . . . . . . . . . . . . . . . . 9-3
Drunk . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3
For Better Fuel Economy . . . . . 1-36
Highway Hypnosis . . . . . . . . . . . . 9-12
Hill and Mountain Roads . . . . . . 9-12
If the Vehicle is Stuck . . . . . . . . . 9-15
Loss of Control . . . . . . . . . . . . . . . . 9-5
Off-Road . . . . . . . . . . . . . . . . . . . . . . 9-6
Off-Road Recovery . . . . . . . . . . . . 9-5
Vehicle Load Limits . . . . . . . . . . . 9-16
Wet Roads . . . . . . . . . . . . . . . . . . . 9-11
Winter . . . . . . . . . . . . . . . . . . . . . . . . 9-13
Dual Automatic Climate
Control System . . . . . . . . . . . . . . . . 8-5
Dual Tire Rotation . . . . . . . . . . . . . . . . . . . . 10-67
DVD Rear Seat Entertainment
System . . . . . . . . . . . . . . . . . . . . . . 7-37
DVD/CD Player . . . . . . . . . . . . . . . . 7-21
E
E85 Fuel . . . . . . . . . . . . . . . . . . . . . . . 9-71
Electrical Equipment, Add-On . . . . . . . . . . . . . . . . . . . . . 9-105
Electrical System Engine CompartmentFuse Block . . . . . . . . . . . . . . . . 10-44
Fuses and Circuit Breakers . . . . . . . . . . . . . . . . . . 10-44
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . . . . 10-48
Overload . . . . . . . . . . . . . . . . . . . 10-43
Emergency, OnStar
®. . . . . . . . . . 14-2
Engine Air Cleaner/Filter . . . . . . . . . . . 10-17
Check and Service EngineSoon Light . . . . . . . . . . . . . . . . . . 5-22
Compartment Overview . . . . . . . 10-6
Coolant . . . . . . . . . . . . . . . . . . . . . 10-19
Coolant Heater . . . . . . . . . . . . . . . 9-30
Coolant Temperature Gauge . . . . . . . . . . . . . . . . . . . . . . 5-16
Cooling System . . . . . . . . . . . . . 10-18