
GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
230 Driving and Operating
Driving on Grades
Reduce speed and shift to a lower
gearbefore starting down a long or
steep downgrade. If the
transmission is not shifted down, the
brakes might get hot and no longer
work well.
Vehicles can tow in D (Drive). Shift
the transmission to a lower gear if
the transmission shifts too often
under heavy loads and/or hilly
conditions.
The Tow/Haul Mode may be used if
the transmission shifts too often.
See Tow/Haul Mode 0199.
When towing at high altitude on
steep uphill grades, consider the
following: Engine coolant will boil at
a lower temperature than at normal
altitudes. If the engine is turned off
immediately after towing at high
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
transmission in P (Park) for a few minutes before turning the engine
off. If the overheat warning comes
on, see
Engine Overheating 0270.
Parking on Hills
{Warning
Parking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface.
If parking the rig on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if
facing downhill or into traffic if
facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the regular
brakes until the chocks absorb
the load. 4. Reapply the brake pedal. Then
apply the parking brake and
shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks.
7. Stop and have someone pick up and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule 0346.
Things that are especially important
in trailer operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
266 Vehicle Care
4. Remove the four screws (1) ontop of the cover of the housing
and lift up the cover.
5. Remove the engine air cleaner/ filter from the housing. Take
care to dislodge as little dirt as
possible.
6. Clean the engine air cleaner/ filter sealing surfaces and the
housing.
7. Inspect or replace the engine air cleaner/filter.
8. Reverse Steps 2–4 to reinstall the filter cover housing.
{Warning
Operating the engine with the air
cleaner/filter off can cause you or
others to be burned. The air
cleaner not only cleans the air; it
helps to stop flames if the engine
backfires. Use caution when
working on the engine and do not
drive with the air cleaner/filter off.
Caution
If the air cleaner/filter is off, dirt
can easily get into the engine,
which could damage it. Always
have the air cleaner/filter in place
when you are driving.
Cooling System
If the vehicle has the Duramax®
diesel engine, see the Duramax
diesel supplement for more
information.
The cooling system allows the
engine to maintain the correct
working temperature.5.3L V8 Engine Shown, 6.2L
V8 Engine Similar
1. Coolant Surge Tank
2. Coolant Surge TankPressure Cap
3. Engine Cooling Fan (Out of View)
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
268 Vehicle Care
Warning (Continued)
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.
. Will not damage aluminum parts.
. Helps keep the proper engine
temperature.
Caution
If improper coolant mixture,
inhibitors, or additives are used in
the vehicle cooling system, the
engine could overheat and be
damaged. Too much water in the
mixture can freeze and crack
engine cooling parts. The repairs
would not be covered by the
vehicle warranty. Use only the
proper mixture of engine coolant
for the cooling system. See
Recommended Fluids and
Lubricants 0355.
Never dispose of engine coolant by
putting it in the trash, or by pouring
it on the ground, or into sewers,
streams, or bodies of water. Have
the coolant changed by an
authorized service center, familiar
with legal requirements regarding
used coolant disposal. This will help
protect the environment and your
health.
Checking Coolant
The coolant surge tank is in the
engine compartment on the
passenger side of the vehicle. See
Engine Compartment Overview
0 255.
The vehicle must be on a level
surface when checking the coolant
level.
Check to see if coolant is visible in
the coolant surge tank. If the coolant
inside the coolant surge tank is
boiling, do not do anything else until
it cools down. If coolant is visible
but the coolant level is not at or
above the FULL COLD mark, add a
50/50 mixture of clean, drinkable
water and DEX-COOL coolant at the
coolant surge tank, but be sure the
cooling system is cool before this
is done.
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
270 Vehicle Care
If no coolant is visible in the surge
tank, add coolant.
Light-Duty
Coolant Surge Tank
Pressure CapHeavy-Duty
Coolant Surge Tank
Pressure Cap
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.
3. Fill the coolant surge tank with the 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 tightly.
6. Verify coolant level after the engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1-6.
Caution
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.
The vehicle has several indicators
to warn of engine overheating.
There is a coolant temperature
gauge in the vehicle's instrument
cluster. See Engine Coolant
Temperature Gauge 0110.
In addition, there are ENGINE
OVERHEATED STOP ENGINE,
ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS
REDUCED messages in the Driver
Information Center (DIC). See
Engine Cooling System Messages
0 128 andEngine Power Messages
0 129.
If the decision is made not to lift the
hood when this warning appears,
get service help right away. See
Roadside Assistance Program
0 367.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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Vehicle Care 271
Then check to see if the engine
cooling fan is running. If the engine
is overheating, the fan should be
running. If it is not, do not continue
to run the engine and have the
vehicle serviced.
Caution
Running the engine without
coolant may cause damage or a
fire. Vehicle damage would not be
covered by the vehicle warranty.
SeeOverheated Engine
Protection Operating Mode 0272
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
(Continued)
Warning (Continued)
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.
SeeOverheated Engine
Protection Operating Mode 0272
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.
. Idles for long periods in traffic.
. Tows a trailer; see Trailer Towing
0 231.
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. When it is safe to do so, pull off the road, shift to P (Park) or
N (Neutral) and let the
engine idle.
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
272 Vehicle Care
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
and have the cooling system
checked for proper fill and function.
If the warning continues, pull over,
stop, and park the vehicle
right away.
If there is still no sign of steam and
the vehicle is equipped with an
engine driven cooling fan, push
down the accelerator until the
engine speed is about twice as fast
as normal idle speed for at least
five minutes while the vehicle is
parked. If the warning is still there,
turn off the engine and get everyone
out of the vehicle until it cools down.
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 itcools down. Also, see
“Overheated
Engine Protection Operating Mode”
following.
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
distances and/or towing a trailer in
the overheat protection mode
should be avoided.
Caution
After driving in the overheated
engine protection operating
mode, the engine oil will be
(Continued)
Caution (Continued)
severely degraded. Any repairs
performed before the engine is
cool may cause engine damage.
Allow the engine to cool before
attempting any repair. Repair the
cause of coolant loss, change the
oil, and reset the oil life system.
SeeEngine Oil 0258.
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
loading, trailer towing, and/or high
outside temperatures, the fan speed
increases as the clutch more fully
engages, so an increase in fan
noise may be heard. This is normal
and should not be mistaken as the
transmission slipping or making
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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274 Vehicle Care
What to Use
To determine what kind of fluid to
use, seeRecommended Fluids and
Lubricants 0355. Always use the
proper fluid.
Caution
Use of the incorrect fluid may
damage the vehicle and the
damages may not be covered by
the vehicle warranty. Always use
the correct fluid listed in
Recommended Fluids and
Lubricants 0355.
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 0255 for
reservoir location.
Caution
. Do not use washer fluid that
contains any type of water
repellent coating. This can
cause the wiper blades to
chatter or skip.
. Do not use engine coolant
(antifreeze) in the
windshield washer. It can
damage the windshield
washer system and paint.
. 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.
. When using concentrated
washer fluid, follow the
manufacturer instructions for
adding water.
. Fill the washer fluid tank
only three-quarters full when
it is very cold. This allows
for fluid expansion if
(Continued)
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GMC Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
9234761) - 2016 - crc - 7/24/15
Index 389
Check (cont'd)Malfunction Indicator
Engine Light . . . . . . . . . . . . . . . . .115
Child Restraints
Infants and Young Children . . . . . 75
Lower Anchors and Tethersfor Children . . . . . . . . . . . . . . . . . . . 80
Older Children . . . . . . . . . . . . . . . . . . 73
Securing . . . . . . . . . . . . . . . . . . . . 87, 89
Systems . . . . . . . . . . . . . . . . . . . . . . . . 77
Cleaning Exterior Care . . . . . . . . . . . . . . . . . 335
Interior Care . . . . . . . . . . . . . . . . . . 340
Climate Control Systems
Dual Automatic . . . . . . . . . . . . . . . 157
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Cluster, Instrument . . . . . . . . . . . . . 106
Collision Damage Repair . . . . . . . 370
Compartments Storage . . . . . . . . . . . . . . . . . . . . . . . . . 94
Compass . . . . . . . . . . . . . . . . . . . . . . . 101 Messages . . . . . . . . . . . . . . . . . . . . 127
Connections
OnStar
®. . . . . . . . . . . . . . . . . . . . . . 379
Control . . . . . . . . . . . . . . . . . . . . . . . . . 210 Traction and ElectronicStability . . . . . . . . . . . . . . . . . . . . . 208 Control Light
Hill Descent . . . . . . . . . . . . . . . . . . .118
Control of a Vehicle . . . . . . . . . . . . . 165
Convex Mirrors . . . . . . . . . . . . . . . . . . 38
Coolant Engine . . . . . . . . . . . . . . . . . . . . . . . . 267
Engine Temperature Gauge . . .110
Engine TemperatureWarning Light . . . . . . . . . . . . . . . 120
Cooling System . . . . . . . . . . . . . . . . . 266 Engine Messages . . . . . . . . . . . . 128
Courtesy Transportation Program . . . . . . . . . . . . . . . . . . . . . . . 369
Cruise Control . . . . . . . . . . . . . . . . . . 211 Light . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Cupholders . . . . . . . . . . . . . . . . . . . . . . 95
Customer Assistance . . . . . . . . . . . 365
Offices . . . . . . . . . . . . . . . . . . . . . . . . 365
Text Telephone (TTY)Users . . . . . . . . . . . . . . . . . . . . . . . 365
Customer Information
Service PublicationsOrdering Information . . . . . . . . 372
Customer Satisfaction Procedure . . . . . . . . . . . . . . . . . . . . . 363
D
Damage Repair, Collision . . . . . . . 370
Danger, Warning, and Caution . . . . 3
Data Recorders, Event . . . . . . . . . 375
Daytime Running
Lamps (DRL) . . . . . . . . . . . . . . . . . . 149
Defensive Driving . . . . . . . . . . . . . . . 165
Delayed Locking . . . . . . . . . . . . . . . . . 32
Diagnostics OnStar
®. . . . . . . . . . . . . . . . . . . . . . 381
Distracted Driving . . . . . . . . . . . . . . . 164
Dome Lamps . . . . . . . . . . . . . . . . . . . 153
Door Ajar Light . . . . . . . . . . . . . . . . . . . . . 122
Ajar Messages . . . . . . . . . . . . . . . 127
Delayed Locking . . . . . . . . . . . . . . . . 32
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Power Locks . . . . . . . . . . . . . . . . . . . . 32
Drive Belt Routing, Engine . . . . . . 362
Driver Assistance Systems . . . . . 214
Driver Information
Center (DIC) . . . . . . . . . . . . . . . . . . 123
Driving Assistance Systems . . . . . . . . . . 218
Characteristics and
Towing Tips . . . . . . . . . . . . . . . . . 228
Defensive . . . . . . . . . . . . . . . . . . . . . 165
Drunk . . . . . . . . . . . . . . . . . . . . . . . . . 165
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