engine GMC SIERRA 1500 2011 Repair Manual

Black plate (15,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-15
Driving Downhill
When off-roading takes you
downhill, consider:
.How steep is the downhill? Will I
be able to maintain vehicle
control?
.What is the surface like?
Smooth? Rough? Slippery?
Hard-packed dirt? Gravel?
.Are there hidden surface
obstacles? Ruts? Logs?
Boulders?
.What is at the bottom of the hill?
Is there a hidden creek bank or
even a river bottom with large
rocks?
If you decide you can go down
a hill safely, try to keep the vehicle
headed straight down. Use a low
gear so engine drag can help the
brakes so they do not have to do all
the work. Descend slowly, keeping
the vehicle under control at all
times.
{WARNING
Heavy braking when going
down a hill can cause your
brakes to overheat and fade.
This could cause loss of control
and a serious accident. Apply the
brakes lightly when descending a
hill and use a low gear to keep
vehicle speed under control.
Things not to do when driving down
a hill:
.When driving downhill, avoid
turns that take you across the
incline of the hill. A hill that is
not too steep to drive down
might be too steep to drive
across. The vehicle could
roll over.
.Never go downhill with the
transmission in N (Neutral),
called free-wheeling. The brakes
will have to do all the work and
could overheat and fade.
Vehicles are much more likely to
stall when going uphill, but if it
happens when going downhill:
1. Stop the vehicle by applying the regular brakes and apply the
parking brake.
2. Shift to P (Park) and, while still braking, restart the engine.
3. Shift back to a low gear, release the parking brake, and drive
straight down.
4. If the engine will not start, get out and get help.

Black plate (18,1)GMC Sierra Owner Manual - 2011
9-18 Driving and Operating
Driving in Water
{WARNING
Driving through rushing water can
be dangerous. Deep water can
sweep your vehicle downstream
and you and your passengers
could drown. If it is only shallow
water, it can still wash away the
ground from under your tires, and
you could lose traction and roll
the vehicle over. Do not drive
through rushing water.
Heavy rain can mean flash flooding,
and flood waters demand extreme
caution. Find out how deep the water is
before driving through it. Do not
try it if it is deep enough to cover
the wheel hubs, axles, or exhaust
pipe
—you probably will not get
through. Deep water can damage
the axle and other vehicle parts.
If the water is not too deep, drive
slowly through it. At faster speeds,
water splashes on the ignition
system and the vehicle can stall.
Stalling can also occur if you get the
tailpipe under water. If the tailpipe is
under water, you will never be able
to start the engine. When going
through water, remember that when
the brakes get wet, it might take
longer to stop. See Driving on Wet
Roads on page 9‑19.
After Off-Road Driving
Remove any brush or debris that
has collected on the underbody,
chassis, or under the hood. These
accumulations can be a fire hazard.
After operation in mud or sand,
have the brake linings cleaned and
checked. These substances can
cause glazing and uneven braking.
Check the body structure, steering,
suspension, wheels, tires, and
exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
The vehicle requires more frequent
service due to off-road use. Refer
to the Maintenance Schedule for
additional information.

Black plate (20,1)GMC Sierra Owner Manual - 2011
9-20 Driving and Operating
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
.Pass with caution.
.Keep windshield wiping
equipment in good shape.
.Keep the windshield washer fluid
reservoir filled.
.Have good tires with proper
tread depth. SeeTires on
page 10‑57.
.Turn off cruise control.
Highway Hypnosis
Always be alert and pay attention
to your surroundings while driving.
If you become tired or sleepy, find
a safe place to park the vehicle
and rest.
Other driving tips include:
.Keep the vehicle well ventilated.
.Keep interior temperature cool.
.Keep your eyes moving —scan
the road ahead and to the sides.
.Check the rearview mirror and
vehicle instruments often.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving
on flat or rolling terrain. Tips for
driving in these conditions include:
.Keep the vehicle serviced and in
good shape.
.Check all fluid levels and brakes,
tires, cooling system, and
transmission.
.Shift to a lower gear when going
down steep or long hills.
{WARNING
If you do not shift down, the
brakes could get so hot that they
would not work well. You would
then have poor braking or even
none going down a hill. You could
crash. Shift down to let the engine
assist the brakes on a steep
downhill slope.

Black plate (21,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-21
{WARNING
Coasting downhill in N (Neutral)
or with the ignition off is
dangerous. The brakes will
have to do all the work of slowing
down and they could get so hot
that they would not work well.
You would then have poor braking
or even none going down a hill.
You could crash. Always have the
engine running and the vehicle in
gear when going downhill.
.Stay in your own lane. Do not
swing wide or cut across the
center of the road. Drive at
speeds that let you stay in
your own lane.
.Top of hills: Be alert—
something could be in your
lane (stalled car, accident).
.Pay attention to special road
signs (falling rocks area, winding
roads, long grades, passing or
no-passing zones) and take
appropriate action.
Winter Driving
Driving on Snow or Ice
Drive carefully when there is snow
or ice between the tires and the
road, creating less traction or grip.
Wet ice can occur at about 0°C
(32°F) when freezing rain begins to
fall, resulting in even less traction.
Avoid driving on wet ice or in
freezing rain until roads can be
treated with salt or sand.
Drive with caution, whatever the
condition. Accelerate gently so
traction is not lost. Accelerating too
quickly causes the wheels to spin
and makes the surface under the
tires slick, so there is even less
traction. Try not to break the fragile traction.
If you accelerate too fast, the drive
wheels will spin and polish the
surface under the tires even more.
The
Antilock Brake System (ABS)
on page 9‑68 improves vehicle
stability during hard stops on
slippery roads, but apply the brakes
sooner than when on dry pavement.
Allow greater following distance on
any slippery road and watch for
slippery spots. Icy patches can
occur on otherwise clear roads in
shaded areas. The surface of a
curve or an overpass can remain
icy when the surrounding roads
are clear. Avoid sudden steering
maneuvers and braking while
on ice.
Turn off cruise control on slippery
surfaces.

Black plate (22,1)GMC Sierra Owner Manual - 2011
9-22 Driving and Operating
Blizzard Conditions
Being stuck in snow can be a
serious situation. Stay with the
vehicle unless there is help nearby.
If possible, use theRoadside
Assistance Program (U.S. and
Canada) on page 13‑8 orRoadside
Assistance Program (Mexico) on
page 13‑10. To get help and keep
everyone in the vehicle safe:
.Turn on the hazard warning
flashers.
.Tie a red cloth to an outside
mirror.
{WARNING
Snow can trap engine exhaust
under the vehicle. This may
cause exhaust gases to get
inside. Engine exhaust contains
Carbon Monoxide (CO) which
cannot be seen or smelled.
It can cause unconsciousness
and even death.
(Continued)
WARNING (Continued)
If the vehicle is stuck in the snow:
.Clear away snow from around
the base of your vehicle,
especially any that is blocking
the exhaust pipe.
.Check again from time to
time to be sure snow does
not collect there.
.Open a window about 5 cm
(2 in) on the side of the
vehicle that is away from
the wind to bring in fresh air.
.Fully open the air outlets
on or under the instrument
panel.
.Adjust the climate control
system to a setting that
circulates the air inside
the vehicle and set the fan
speed to the highest setting.
See Climate Control System
in the Index.(Continued)
WARNING (Continued)
For more information about
carbon monoxide, see Engine
Exhaust on page 9‑44.
Snow can trap exhaust gases
under your vehicle. This can
cause deadly CO (Carbon
Monoxide) gas to get inside.
CO could overcome you and kill
you. You cannot see it or smell it,
so you might not know it is in your
vehicle. Clear away snow from
around the base of your vehicle,
especially any that is blocking the
exhaust.
Run the engine for short periods
only as needed to keep warm, but
be careful.

Black plate (23,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-23
To save fuel, run the engine for only
short periods as needed to warm
the vehicle and then shut the engine
off and close the window most of
the way to save heat. Repeat this
until help arrives but only when you
feel really uncomfortable from the
cold. Moving about to keep warm
also helps.
If it takes some time for help to
arrive, now and then when you run
the engine, push the accelerator
pedal slightly so the engine runs
faster than the idle speed. This
keeps the battery charged to restart
the vehicle and to signal for help
with the headlamps. Do this as little
as possible to save fuel.If the Vehicle is Stuck
Slowly and cautiously spin the
wheels to free the vehicle when
stuck in sand, mud, ice, or snow.
See“Rocking Your Vehicle to Get
It Out” later in this section.
If the vehicle has a traction system,
it can often help to free a stuck
vehicle. Refer to the vehicle's
traction system in the Index. If stuck
too severely for the traction system
to free the vehicle, turn the traction
system off and use the rocking
method.{WARNING
If the vehicle's tires spin at high
speed, they can explode, and
you or others could be injured.
The vehicle can overheat,
causing an engine compartment
fire or other damage. Spin the
wheels as little as possible and
avoid going above 55 km/h
(35 mph).
For information about using tire
chains on the vehicle, see Tire
Chains on page 10‑83.

Black plate (34,1)GMC Sierra Owner Manual - 2011
9-34 Driving and Operating
When the truck‐camper is
loaded, drive to a scale and
weigh on the front and on the
rear wheels separately to
determine axle loads. Individual
axle loads should not exceed
either of the gross axle weight
ratings (GAWR). The total axle
loads should not exceed your
vehicle's gross vehicle weight
rating (GVWR). These ratings
are given on the vehicle
certification label attached to
the rear edge of the driver door.
See“Certification/Tire Label”
under Vehicle Load Limits on
page 9‑25. If weight ratings
are exceeded, move or remove
items to bring all weights below
the ratings.
See your dealer for more
information on curb weights,
cargo weights, Cargo Weight
Rating and the correct center
of gravity zone.Starting and
Operating
New Vehicle Break-In
Notice: The vehicle does not
need an elaborate break-in. But it
will perform better in the long run
if you follow these guidelines:
.Keep the vehicle speed at
88 km/h (55 mph) or less for
the first 805 km (500 miles).
.Do not drive at any one
constant speed, fast or
slow, for the first 805 km
(500 miles). Do not make
full-throttle starts. Avoid
downshifting to brake or
slow the vehicle.
.Avoid making hard stops for
the first 322 km (200 miles)
or so. During this time the
new brake linings are not
yet broken in. Hard stops
with new linings can mean
premature wear and earlier
replacement. Follow this
breaking-in guideline every
time you get new brake
linings.
.Do not tow a trailer during
break-in. See Trailer
Towing on page 9‑95 for the
trailer towing capabilities
of the vehicle and more
information.
Following break‐in, engine speed
and load can be gradually
increased.

Black plate (36,1)GMC Sierra Owner Manual - 2011
9-36 Driving and Operating
A (STOPPING THE ENGINE/
LOCK/OFF):When the vehicle is
stopped, turn the ignition switch to
LOCK/OFF to turn the engine off.
Retained Accessory Power (RAP)
will remain active. See Retained
Accessory Power (RAP) on
page 9‑40.
This position locks the ignition.
It also locks the transmission on
automatic transmission vehicles.
The key can be removed in
LOCK/OFF.
Do not turn the engine off when the
vehicle is moving. This will cause a
loss of power assist in the brake
and steering systems and disable
the airbags. In an emergency:
1. Brake using a firm and steady
pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to neutral. This can be done while the vehicle is
moving. After shifting to neutral,
firmly apply the brakes and steer
the vehicle to a safe location.
3. Come to a complete stop, shift to P (Park), and turn the ignition
to LOCK/OFF. On vehicles with
an automatic transmission, the
shift lever must be in P (Park)
to turn the ignition switch to the
LOCK/OFF position.
4. Set the parking brake. See Parking Brake on page 9‑69. The steering can bind with the
wheels turned off center. If this
happens, move the steering wheel
from right to left while turning the
key to ACC/ACCESSORY. If this
doesn't work, then the vehicle
needs service.
Notice:
Using a tool to force the
key to turn in the ignition could
cause damage to the switch or
break the key. Use the correct
key, make sure it is all the way in,
and turn it only with your hand.
If the key cannot be turned by
hand, see your dealer.
B (ACC/ACCESSORY): This
position lets things like the radio
and the windshield wipers operate
while the engine is off. Use this
position if the vehicle must be
pushed or towed.

Black plate (37,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-37
C (ON/RUN):This position can
be used to operate the electrical
accessories and to display some
instrument panel cluster warning
and indicator lights. The switch
stays in this position when the
engine is running. The transmission
is also unlocked in this position on
automatic transmission vehicles.
If you leave the key in the
ACC/ACCESSORY or ON/RUN
position with the engine off, the
battery could be drained. You may
not be able to start the vehicle if the
battery is allowed to drain for an
extended period of time.
D (START): This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when
the driver door is opened and the
ignition is in ACC/ACCESSORY or
LOCK/OFF, and the key is in the
ignition.Starting the Engine
If the vehicle has a Duramax diesel
engine, see the Duramax diesel
supplement for more information.
If the vehicle is a hybrid, see
the hybrid supplement for more
information.
Notice: Do not try to shift to
P (Park) if the vehicle is moving.
If you do, you could damage the
transmission. Shift to P (Park)
only when the vehicle is stopped.
Move the shift lever to P (Park) or
N (Neutral). The engine will not start
in any other position. To restart the
engine when the vehicle is already
moving, use N (Neutral) only.
Notice: The engine is designed to
work with the electronics in the
vehicle. If you add electrical parts
or accessories, you could change
the way the engine operates. Before adding electrical
equipment, check with your
dealer. If you do not, the engine
might not perform properly.
Any resulting damage would
not be covered by the vehicle
warranty.
Starting Procedure
1. With your foot off the accelerator
pedal, turn the ignition key to
START. When the engine starts,
let go of the key. The idle speed
will go down as your engine gets
warm. Do not race the engine
immediately after starting it.
Operate the engine and
transmission gently to allow
the oil to warm up and lubricate
all moving parts.

Black plate (38,1)GMC Sierra Owner Manual - 2011
9-38 Driving and Operating
The vehicle has a
Computer-Controlled
Cranking System. This feature
assists in starting the engine
and protects components.
If the ignition key is turned
to the START position, and
then released when the engine
begins cranking, the engine
will continue cranking for a
few seconds or until the vehicle
starts. If the engine does not
start and the key is held in
START for many seconds,
cranking will be stopped after
15 seconds to prevent cranking
motor damage. To prevent
gear damage, this system also
prevents cranking if the engine
is already running. Engine
cranking can be stopped by
turning the ignition switch to
the ACC/ACCESSORY or
LOCK/OFF position.When the Low Fuel warning
lamp is on and the FUEL LEVEL
LOW message is displayed in
the Driver Information Center
(DIC), the Computer‐Controlled
Cranking System is disabled
to prevent possible vehicle
component damage. When
this happens, hold the ignition
switch in the START position
to continue engine cranking.
Notice: Cranking the engine for
long periods of time, by returning
the key to the START position
immediately after cranking has
ended, can overheat and damage
the cranking motor, and drain the
battery. Wait at least 15 seconds
between each try, to let the
cranking motor cool down. 2. If the engine does not start
after 5‐10 seconds, especially
in very cold weather (below
−18°C or 0°F), it could be
flooded with too much gasoline.
Try pushing the accelerator
pedal all the way to the floor
and holding it there as you
hold the key in START for up
to 15 seconds. Wait at least
15 seconds between each try, to
allow the cranking motor to cool
down. When the engine starts,
let go of the key and accelerator.
If the vehicle starts briefly but
then stops again, do the same
thing. This clears the extra
gasoline from the engine. Do not
race the engine immediately
after starting it. Operate the
engine and transmission gently
until the oil warms up and
lubricates all moving parts.