2012 GMC SIERRA 1500 overheating

Black plate (19,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-19
{WARNING
Heater and radiator hoses, and
other engine parts, can be very
hot. Do not touch them. If you do,
you can be burned.
Do not run the engine if there is a
leak. If you run the engine, it
could lose all coolant. That could
cause an engine fire, and you
could be burned. Get any leak
fixed before you drive the vehicle.
Notice: Using coolant other than
DEX-COOL
®can cause premature
engine, heater core, or radiator
corrosion. In addition, the engine
coolant could require changing
sooner, at 50 000 km (30,000 mi)
or 24 months, whichever occurs
first. Any repairs would not
be covered by the vehicle
warranty. Always use DEX-COOL
(silicate-free) coolant in the
vehicle.
Engine Coolant
The cooling system in the vehicle
is filled with DEX-COOL®engine
coolant. This coolant is designed to
remain in the vehicle for 5 years or
240 000 km (150,000 mi), whichever
occurs first.
The following explains the cooling
system and how to check and add
coolant when it is low. If there is a
problem with engine overheating,
see Engine Overheating on
page 10‑22.
What to Use
{WARNING
Adding only plain water or some
other liquid to the cooling system
can be dangerous. Plain water
and other liquids, can boil before
the proper coolant mixture will.
The coolant warning system is set
for the proper coolant mixture.
With plain water or the wrong
(Continued)
WARNING (Continued)
mixture, the engine could get too
hot but you would not get the
overheat warning. The engine
could catch fire and you or
others could be burned. Use a
50/50 mixture of clean, drinkable
water and DEX-COOL coolant.
Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
coolant. If using this mixture,
nothing else needs to be added.
This mixture:
.Gives freezing protection down
to −37°C (−34°F), outside
temperature
.Gives boiling protection up to
129°C (265°F), engine
temperature
.Protects against rust and
corrosion

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 (50,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-50 Vehicle Care
Top View
Harness
Connector Usage
BODY 2 Body Harness
Connector 2
BODY 1 Body Harness
Connector 1
BODY 3 Body Harness
Connector 3
HEADLINER 3 Headliner
Harness
Connector 3 Harness
Connector Usage
HEADLINER 2 Headliner
Harness
Connector 2
HEADLINER 1 Headliner
Harness
Connector 1
SEO/
UPFITTER Special
Equipment Option
Upfitter Harness
Connector
Circuit
Breaker Usage
CB1 Passenger Side
Power Window Circuit
Breaker
CB2 Passenger Seat
Circuit Breaker
CB3 Driver Seat Circuit
Breaker
CB4 Rear Sliding Window
Wheels and Tires
Tires
Every new GM vehicle has
high-quality tires made by a
leading tire manufacturer.
See the warranty manual for
information regarding the tire
warranty and where to get
service. For additional
information refer to the tire
manufacturer.
{WARNING
.Poorly maintained and
improperly used tires are
dangerous.
.Overloading the tires can
cause overheating as a result
of too much flexing. There
could be a blowout and a
serious crash. See Vehicle
Load Limits on page 9‑16.
(Continued)

Black plate (58,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-58 Vehicle Care
Treadwear Indicators:Narrow
bands, sometimes called wear
bars, that show across the tread
of a tire when only 1.6 mm
(1/16 in) of tread remains. See
When It Is Time for New Tires
on page 10‑68.
UTQGS (Uniform Tire Quality
Grading Standards)
:A tire
information system that
provides consumers with
ratings for a tire's traction,
temperature, and treadwear.
Ratings are determined
by tire manufacturers using
government testing procedures.
The ratings are molded into
the sidewall of the tire. See
Uniform Tire Quality Grading on
page 10‑70. Vehicle Capacity Weight
:
The number of designated
seating positions multiplied by
68 kg (150 lbs) plus the rated
cargo load. See
Vehicle Load
Limits on page 9‑16.
Vehicle Maximum Load on the
Tire
:Load on an individual tire
due to curb weight, accessory
weight, occupant weight, and
cargo weight.
Vehicle Placard
:A label
permanently attached to a
vehicle showing the vehicle
capacity weight and the
original equipment tire size
and recommended inflation
pressure. See “Tire and Loading
Information Label” underVehicle
Load Limits on page 9‑16.
Tire Pressure
Tires need the correct amount
of air pressure to operate
effectively.
Notice: Neither tire
underinflation nor
overinflation is good.
Underinflated tires, or tires
that do not have enough air,
can result in:
.Tire overloading and
overheating which could
lead to a blowout.
.Premature or
irregular wear.
.Poor handling.
.Reduced fuel economy.

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