engine GMC SIERRA CLASSIC 2007 Manual PDF

Driving Downhill
When off-roading takes you downhill, you will want
to consider a number of things:
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, then
try to keep your vehicle headed straight down, and
use a low gear. This way, engine drag can help
the brakes and they will not have to do all
the work. Descend slowly, keeping your vehicle
under control at all times.
{CAUTION:
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.
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Q:Are there some things I should not do
when driving down a hill?
A:Yes! These are important because if you
ignore them you could lose control and
have a serious accident.
When driving downhill, avoid turns that take
you across the incline of the hill. A hill that
is not too steep to drive down may be
too steep to drive across. You could roll
over if you do not drive straight down.
Never go downhill with the transmission in
NEUTRAL (N), or with the clutch pedal
pressed down with a manual transmission.
This is called “free-wheeling.” The brakes will
have to do all the work and could overheat
and fade.
Q:Am I likely to stall when going downhill?
A:It is much more likely to happen going
uphill. But if it happens going downhill,
here is what to do.
1. Stop your vehicle by applying the regular
brakes. Apply the parking brake.
2. Shift to PARK (P), or to NEUTRAL with the
manual transmission, 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.
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Driving in Water
Heavy rain can mean ash ooding, and ood
waters demand extreme caution.
Find out how deep the water is before you drive
through it. If it is deep enough to cover the wheel
hubs, axles, or exhaust pipe, do not try it — you
probably will not get through. Also, water that deep
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 your vehicle can stall. Stalling can also
occur if you get the tailpipe under water. And,
as long as the tailpipe is under water, you will
never be able to start the engine. When you go
through water, remember that when the brakes get
wet, it may take you longer to stop.{CAUTION:
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.
SeeDriving in Rain and on Wet Roads on page 392
for more information on driving through water.
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Hydroplaning
Hydroplaning is dangerous. So much water can
build up under your tires that they can actually ride
on the water. This can happen if the road is wet
enough and you are going fast enough. When your
vehicle is hydroplaning, it has little or no contact
with the road.
Hydroplaning does not happen often. But it can
if your tires do not have much tread or if the
pressure in one or more is low. It can happen if a
lot of water is standing on the road. If you can
see reections from trees, telephone poles,
or other vehicles, and raindrops dimple the water’s
surface, there could be hydroplaning.
Hydroplaning usually happens at higher speeds.
There just is not a hard and fast rule about
hydroplaning. The best advice is to slow down
when it is raining.
Driving Through Deep Standing Water
Notice:If you drive too quickly through
deep puddles or standing water, water can
come in through your engine’s air intake and
badly damage your engine. Never drive through
water that is slightly lower than the underbody
of your vehicle. If you cannot avoid deep
puddles or standing water, drive through them
very slowly.
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Here are some things you can check before a trip:
Windshield Washer Fluid:Is the reservoir
full? Are all windows clean inside and outside?
Wiper Blades:Are they in good shape?
Fuel, Engine Oil, Other Fluids:Have you
checked all levels?
Lamps:Are they all working? Are the lenses
clean?
Tires:They are vitally important to a safe,
trouble-free trip. Is the tread good enough
for long-distance driving? Are the tires
all inated to the recommended pressure?
Weather Forecasts:What is the weather
outlook along your route? Should you
delay your trip a short time to avoid a major
storm system?
Maps:Do you have up-to-date maps?
Highway Hypnosis
Is there actually such a condition as highway
hypnosis? Or is it just plain falling asleep at the
wheel? Call it highway hypnosis, lack of
awareness, or whatever.
There is something about an easy stretch of road
with the same scenery, along with the hum of the
tires on the road, the drone of the engine, and the
rush of the wind against the vehicle that can make
you sleepy. Do not let it happen to you! If it does,
your vehicle can leave the road in less than a
second, and you could crash and be injured.
What can you do about highway hypnosis?
First, be aware that it can happen.
Then here are some tips:
Make sure your vehicle is well ventilated,
with a comfortably cool interior.
Keep your eyes moving. Scan the road ahead
and to the sides. Check your mirrors and your
instruments frequently.
If you get sleepy, pull off the road into a rest,
service, or parking area and take a nap, get
some exercise, or both. For safety, treat
drowsiness on the highway as an emergency.
399

Hill and Mountain Roads
Driving on steep hills or mountains is different
from driving in at or rolling terrain.If you drive regularly in steep country, or if you are
planning to visit there, here are some tips that
can make your trips safer and more enjoyable.
SeeOff-Road Driving on page 372for information
about driving off-road.
Keep your vehicle in good shape. Check all
uid levels and also the brakes, tires, cooling
system, and transmission. These parts can
work hard on mountain roads.
{CAUTION:
If you do not shift down, your 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 your engine assist
your brakes on a steep downhill slope.
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{CAUTION:
Coasting downhill in NEUTRAL (N) or with
the ignition off is dangerous. Your brakes
will have to do all the work of slowing
down. 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 your
engine running and your vehicle in gear
when you go downhill.
Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift to a lower gear when
you go down a steep or long hill.
Know how to go uphill. You may want to shift
down to a lower gear. The lower gears help
cool your engine and transmission, and you can
climb the hill better.
Stay in your own lane when driving on two-lane
roads in hills or mountains. Do not swing wide
or cut across the center of the road. Drive at
speeds that let you stay in your own lane.
As you go over the top of a hill, be alert.
There could be something in your lane, like a
stalled car or an accident.
You may see highway signs on mountains that
warn of special problems. Examples are long
grades, passing or no-passing zones, a falling
rocks area, or winding roads. Be alert to these
and take appropriate action.
401

You can run the engine to keep warm, but be
careful.
{CAUTION:
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 your exhaust pipe. And
check around again from time to time to
be sure snow does not collect there.
Open a window just a little on the side of
the vehicle that is away from the wind.
This will help keep CO out.
Run your engine only as long as you must.
This saves fuel. When you run the engine, make it
go a little faster than just idle. That is, push the
accelerator slightly. This uses less fuel for the heat
that you get and it keeps the battery charged.
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You will need a well-charged battery to restart the
vehicle, and possibly for signaling later on with
your headlamps. Let the heater run for a while.
Then, shut the engine off and close the window
almost all the way to preserve the heat. Start
the engine again and repeat this only when you
feel really uncomfortable from the cold. But do it as
little as possible. Preserve the fuel as long as
you can. To help keep warm, you can get out of
the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
In order to free your vehicle when it is stuck,
you will need to spin the wheels, but you do not
want to spin your wheels too fast. The method
known as rocking can help you get out when you
are stuck, but you must use caution.
{CAUTION:
If you let your vehicle’s tires spin at high
speed, they can explode, and you or others
could be injured. And, the transmission or
other parts of the vehicle can overheat.
That could cause an engine compartment
re or other damage. When you are stuck,
spin the wheels as little as possible. Do not
spin the wheels above 35 mph (55 km/h) as
shown on the speedometer.
406

Four-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle:
1. Shift an automatic transmission to PARK (P),
or a manual transmission to FIRST (1).
2. Turn the engine off, but leave the ignition on.
3. Firmly set the parking brake.
4. Securely attach the vehicle being towed to the
tow vehicle.
{CAUTION:
Shifting a four-wheel-drive vehicle’s
transfer case into NEUTRAL can cause
your vehicle to roll even if the transmission
is in PARK (P) for an automatic
transmission, or if your vehicle is in gear,
for a manual transmission. You or others
could be injured. Make sure the parking
brake is rmly set before you shift the
transfer case to NEUTRAL.
5. Shift the transfer case to NEUTRAL.
SeeFour-Wheel Drive on page 153for the
proper procedure to select the neutral position
for your vehicle.
6. Release the parking brake only after the
vehicle being towed is rmly attached to
the towing vehicle.
7. Turn the ignition off and leave the steering
column unlocked.
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