2012 GMC SIERRA 1500 engine overheat

Black plate (21,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-21
How to Add Coolant to the
Coolant Surge Tank for
Gasoline Engines
If the vehicle has a diesel engine,
see“Cooling System” in the
Duramax Diesel Supplement for
the proper coolant fill procedure.
{WARNING
You can be burned if you spill
coolant on hot engine parts.
Coolant contains ethylene glycol
and it will burn if the engine parts
are hot enough. Do not spill
coolant on a hot engine.
Notice: This vehicle has a
specific coolant fill procedure.
Failure to follow this procedure
could cause the engine to
overheat and be severely
damaged.
{WARNING
An electric engine cooling fan
under the hood can start up even
when the engine is not running
and can cause injury. Keep
hands, clothing, and tools away
from any underhood electric fan.
{WARNING
Steam and scalding liquids from a
hot cooling system can blow out
and burn you badly. They are
under pressure, and if you turn
the coolant surge tank pressure
cap —even a little —they can
come out at high speed. Never
turn the cap when the cooling
system, including the coolant
surge tank pressure cap, is hot.
Wait for the cooling system and
coolant surge tank pressure cap
to cool if you ever have to turn
the pressure cap. If no coolant is visible in the surge
tank, add coolant as follows:
1. Remove the coolant surge tank
pressure cap when the cooling
system, including the coolant
surge tank pressure cap and
upper radiator hose, is no
longer hot.
Turn the pressure cap slowly
counterclockwise about one full
turn. If a hiss is heard, wait for
that to stop. A hiss means there
is still some pressure left.
2. Keep turning the pressure cap slowly, and remove it.

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 (44,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-44 Vehicle Care
Headlamp Wiring
An electrical overload may cause
the lamps to go on and off, or in
some cases to remain off. Have
the headlamp wiring checked right
away if the lamps go on and off or
remain off.
Windshield Wipers
If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop until the motor cools
and will then restart.
Although the circuit is protected
from electrical overload, overload
due to heavy snow or ice may
cause wiper linkage damage.
Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses and Circuit
Breakers
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
The wiring circuits in the vehicle
are protected from short circuits
by a combination of fuses, circuit
breakers and fusible thermal links.
This greatly reduces the chance of
fires caused by electrical problems.
Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you replace a bad fuse with a new
one of the identical size and rating.If you ever have a problem on the
road and don't have a spare fuse,
you can borrow one that has the
same amperage. Just pick some
feature of your vehicle that you can
get along without–
like the radio or
accessory power outlet– and use its
fuse, if it is the correct amperage.
Replace it as soon as you can.
Engine Compartment
Fuse Block
If the vehicle has a diesel engine,
see the Duramax Diesel supplement
for more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.

Black plate (5,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
INDEX i-5
Engine (cont'd)Cooling System Messages . . . 5-41
Drive Belt Routing . . . . . . . . . . . . 12-6
Exhaust . . . . . . . . . . . . . . . . . . . . . . 9-33
Fan . . . . . . . . . . . . . . . . . . . . . . . . . 10-24
Oil Life System . . . . . . . . . . . . . 10-10
Oil Messages . . . . . . . . . . . . . . . . . 5-42
Oil Pressure Gauge . . . . . . . . . . 5-15
Overheated Protection
Operating Mode . . . . . . . . . . . 10-24
Overheating . . . . . . . . . . . . . . . . 10-22
Power Messages . . . . . . . . . . . . . 5-42
Pressure Light . . . . . . . . . . . . . . . . 5-28
Running While Parked . . . . . . . . 9-34
Starting . . . . . . . . . . . . . . . . . . . . . . . 9-27
Entry Lighting . . . . . . . . . . . . . . . . . . . 6-9
Equipment, Towing . . . . . . . . . . . . 9-94
Event Data Recorders . . . . . . . . 13-19
Exit Lighting . . . . . . . . . . . . . . . . . . . . 6-9
Extender, Safety Belt . . . . . . . . . . 3-20
Exterior Lamp Controls . . . . . . . . . 6-1
Exterior Lamps Off Reminder . . . 6-2F
Fan Engine . . . . . . . . . . . . . . . . . . . . . . 10-24
Fast Idle System . . . . . . . . . . . . . . . 9-29
Features Memory . . . . . . . . . . . . . . . . . . . . . . . 1-14
Filter,
Engine Air Cleaner . . . . . . . . . 10-17
Flash-to-Pass . . . . . . . . . . . . . . . . . . . 6-3
Flashers, Hazard Warning . . . . . . 6-5
Flat Tire . . . . . . . . . . . . . . . . . . . . . . 10-75 Changing . . . . . . . . . . . . . . . . . . . 10-76
Floor Mats . . . . . . . . . . . . . . . . . . .10-104
Fluid AutomaticTransmission . . . . . . . 10-11, 10-14
Brakes . . . . . . . . . . . . . . . . . . . . . . 10-28
Four-Wheel Drive Transfer Case . . . . . . . . . . . . . . . 9-40
Power Steering . . . . . . . . . . . . . 10-25
Washer . . . . . . . . . . . . . . . . . . . . . 10-26 Fog Lamps
Bulb Replacement . . . . . . . . . . . . . 6-6
Folding Mirrors . . . . . . . . . . . . . . . . 2-16
Four-Wheel Drive . . . . . . . 9-40, 10-30
Four-Wheel-Drive Light . . . . . . . . 5-26
Front Axle . . . . . . . . . . . . . . . . . . . . 10-31
Front Fog Lamp Light . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29
Front Seats Adjustment . . . . . . . . . . . . . . . . . . . . 3-3
Heated and Ventilated . . . . . . . . . 3-9
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-68 Additives . . . . . . . . . . . . . . . . . . . . . 9-70
E85 (85% Ethanol) . . . . . . . . . . . 9-71
Economy Driving . . . . . . . . . . . . . 1-36
Filling a Portable FuelContainer . . . . . . . . . . . . . . . . . . . 9-73
Filling the Tank . . . . . . . . . . . . . . . 9-72
Foreign Countries . . . . . . . . . . . . 9-69
Gasoline Specifications . . . . . . . 9-69
Gauge . . . . . . . . . . . . . . . . . . . . . . . . 5-14
Low Fuel Warning Light . . . . . . . 5-28

Black plate (9,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
INDEX i-9
MirrorsAutomatic Dimming
Rearview . . . . . . . . . . . . . . . . . . . . 2-18
Convex . . . . . . . . . . . . . . . . . . . . . . . 2-14
Folding . . . . . . . . . . . . . . . . . . . . . . . 2-16
Heated . . . . . . . . . . . . . . . . . . . . . . . 2-17
Manual . . . . . . . . . . . . . . . . . . . . . . . 2-14
Manual Rearview . . . . . . . . . . . . . 2-18
Park Tilt . . . . . . . . . . . . . . . . . . . . . . 2-17
Power . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Trailer Tow . . . . . . . . . . . . . . . . . . . . 2-15
Monitor System, Tire Pressure . . . . . . . . . . . . . . . . . . . . 10-60
N
NavigationOnStar®. . . . . . . . . . . . . . . . . . . . . . 14-2
Vehicle Data Recording
and Privacy . . . . . . . . . . . . . . . 13-20
New Vehicle Break-In . . . . . . . . . . 9-25
Noise Control System . . . . . . . . 10-34
O
Object Detection System Messages . . . . . . . . . . . . . . . . . . . . 5-43
Odometer . . . . . . . . . . . . . . . . . . . . . . 5-13 Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
Off-Road . . . . . . . . . . . . . . . . . . . . . . . 9-6 Driving . . . . . . . . . . . . . . . . . . . . . . . . . 9-6
Recovery . . . . . . . . . . . . . . . . . . . . . . 9-5
Oil Engine . . . . . . . . . . . . . . . . . . . . . . . . 10-7
Engine Oil Life System . . . . . 10-10
Engine Oil PressureGauge . . . . . . . . . . . . . . . . . . . . . . 5-15
Messages . . . . . . . . . . . . . . . . . . . . 5-42
Pressure Light . . . . . . . . . . . . . . . . 5-28
Older Children, Restraints . . . . . 3-39
Online Owner Center . . . . . . . . . . 13-6
OnStar
®
Additional Information . . . . . . . . 14-5
Connections . . . . . . . . . . . . . . . . . . 14-4
Diagnostics . . . . . . . . . . . . . . . . . . . 14-5
Emergency . . . . . . . . . . . . . . . . . . . 14-2 OnStar
®(cont'd)
Navigation . . . . . . . . . . . . . . . . . . . . 14-2
Overview . . . . . . . . . . . . . . . . . . . . . 14-1
Security . . . . . . . . . . . . . . . . . . . . . . 14-2
System, In Brief . . . . . . . . . . . . . . 1-37
Operation, Infotainment System . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Ordering Service Publications . . . . . . . . 13-16
Outlets Power . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Overheated Engine Protection
Operating Mode . . . . . . . . . . . . . 10-24
Overheating, Engine . . . . . . . . . . 10-22
Overview, OnStar
®. . . . . . . . . . . . 14-1
P
Park Shifting Into . . . . . . . . . . . . . . . . . . . 9-30
Shifting Out of . . . . . . . . . . . . . . . . 9-32
Tilt Mirrors . . . . . . . . . . . . . . . . . . . . 2-17