engine CHEVROLET EXPRESS CARGO VAN 2007 1.G Service Manual

Hill and Mountain Roads
Driving on steep hills or mountains is different
from driving in flat 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.
•Keep your vehicle in good shape. Check
all fluid 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, 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.
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{CAUTION:
Coasting downhill in NEUTRAL (N) or with
the ignition off is dangerous. The 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 the
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 the engine do some of
the slowing down. Shift to a lower gear when
you go down a steep or long hill.
•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 might 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.
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If You Are Caught in a Blizzard
If you are stopped by heavy snow, you could be in
a serious situation. You should probably stay
with your vehicle unless you know for sure that you
are near help and you can hike through the
snow. Here are some things to do to summon
help and keep yourself and your passengers safe:
•Turn on your hazard flashers.
•Tie a red cloth to your vehicle to alert police
that you have been stopped by the snow.
•Put on extra clothing or wrap a blanket around
you. If you do not have blankets or extra
clothing, make body insulators from
newspapers, burlap bags, rags, floor
mats — anything you can wrap around
yourself or tuck under your clothing to
keep warm.You can run the engine to keep warm, but
be careful.
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{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 the
exhaust pipe and/or the fuel operated
heater exhaust system, if equipped. And
check around again from time to time to
be sure snow does not collect there. If
your vehicle has a diesel engine and a
fuel operated heater, see “Fuel Operated
Heater (FOH)” in the diesel engine
supplement.
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 (or batteries)
charged. You will need a well-charged battery (or
batteries) 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.
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If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
In order to free your vehicle when it is stuck, you
need to spin the wheels, but you do not want
to spin the 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.Notice:Spinning the wheels can destroy parts
of your vehicle as well as the tires. If you
spin the wheels too fast while shifting
the transmission back and forth, you can
destroy the transmission.
For information about using tire chains on your
vehicle, seeTire Chains on page 364.
Rocking Your Vehicle to Get It Out
First, turn the steering wheel left and right.
That will clear the area around the front wheels.
Then shift back and forth between REVERSE (R)
and a forward gear, spinning the wheels as
little as possible. Release the accelerator pedal
while you shift, and press lightly on the accelerator
pedal when the transmission is in gear. By
slowly spinning the wheels in the forward and
reverse directions, you will cause a rocking motion
that may free your vehicle. If that does not get
your vehicle out after a few tries, it may need to be
towed out. If your vehicle does need to be
towed out, seeTowing Your Vehicle on page 266.
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Towing a Trailer
If your vehicle has a diesel engine, see the
DURAMAX®Diesel manual for more information.
{CAUTION:
If you do not use the correct equipment
and drive properly, you can lose control
when you pull a trailer. For example, if the
trailer is too heavy, the brakes may not
work well — or even at all. You and your
passengers could be seriously injured.
You may also damage your vehicle; the
resulting repairs would not be covered by
your warranty. Pull a trailer only if you
have followed all the steps in this section.
Ask your dealer/retailer for advice and
information about towing a trailer with
your vehicle.Notice:Pulling a trailer improperly can
damage your vehicle and result in costly repairs
that would not be covered by your warranty.
Always follow the instructions in this section
and check with your dealer/retailer for more
information about towing a trailer with your
vehicle.
To identify the trailering capacity of your vehicle,
you should read the information in “Weight of
the Trailer” that appears later in this section.
Trailering is different than just driving your vehicle
by itself. Trailering means changes in acceleration,
braking, handling, durability and fuel economy.
Successful, safe trailering takes correct equipment,
and it has to be used properly.
That’s the reason for this part. In it are many
time-tested, important trailering tips and safety
rules. Many of these are important for your safety
and that of your passengers. So please read
this section carefully before you pull a trailer.
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If You Do Decide To Pull A Trailer
If you do, here are some important points:
•There are many different laws, including speed
limit restrictions, having to do with trailering.
Make sure your rig will be legal, not only where
you live but also where you’ll be driving. A
good source for this information can be state
or provincial police.
•Consider using a sway control. See “Hitches”
later in this section.
•Don’t tow a trailer at all during the first
500 miles (800 km) your new vehicle is driven.
Your engine, axle or other parts could be
damaged.
•Then, during the first 500 miles (800 km) that
you tow a trailer, don’t drive over 50 mph
(80 km/h) and don’t make starts at full throttle.
This helps your engine and other parts of
your vehicle wear in at the heavier loads.
•See also “Driving on Grades” later in this
section.Three important considerations have to do
with weight:
•the weight of the trailer
•the weight of the trailer tongue
•and the weight on your vehicle’s tires
Tow/Haul Mode
Tow/haul is designed to assist while your vehicle
is pulling a large or heavy load or trailer.
Tow/haul is most useful while pulling such a load
in rolling terrain, in stop-and-go traffic, or when
you need improved low-speed control, such
as when parking. The purpose of the tow/haul
mode is to:
•Reduce the frequency and improve the
predictability of transmission shifts,
•provide the same solid shift feel when pulling
a heavy load as when the vehicle is unloaded,
•improve control of vehicle speed while
requiring less throttle pedal activity.
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Press this button
located to the right of
the steering wheel
on the instrument panel
to turn tow/haul
mode on and off.
While activated, the
indicator light on the
instrument panel will
be on.
Tow/haul mode will turn off automatically when the
ignition is turned off. SeeTow/Haul Mode Light
on page 185.
Tow/haul is most effective when the vehicle and
trailer combined weight is at least 75 percent of the
vehicle’s Gross Combined Weight Rating (GCWR).
See “Weight of the Trailer” later in this section.
Driving with tow/haul activated without a heavy
load will cause reduced fuel economy and
unpleasant engine and transmission driving
characteristics, but will not cause damage.Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig. For
example, speed, altitude, road grades, outside
temperature and how much your vehicle is used to
pull a trailer are all important. It can also depend
on any special equipment that you have on
your vehicle, and the amount of tongue weight the
vehicle can carry. See “Weight of the Trailer
Tongue” later in this section for more information.
Maximum trailer weight is calculated assuming
only the driver is in the tow vehicle and it has all
the required trailering equipment. The weight
of additional optional equipment, passengers and
cargo in the tow vehicle must be subtracted
from the maximum trailer weight.
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If you’ll be pulling a trailer that, when loaded, will
weigh more than 5,000 lbs (2 270 kg), be sure
to use a properly mounted weight-distributing hitch
and sway control of the proper size. This
equipment is very important for proper vehicle
loading and good handling when you’re driving.
You should always use a sway control if your
trailer will weigh more than these limits. You can
ask a hitch dealer/retailer about sway controls.
Will you have to make any holes in the body
of your vehicle when you install a trailer hitch?
If you’re using the wiring provided with the
factory-installed trailering package, you should not
need to make any holes in the body of your vehicle.
However, if you have an aftermarket hitch installed,
you may need to make holes in the body.
If you do, then be sure to seal the holes later
when you remove the hitch. If you don’t seal them,
deadly carbon monoxide (CO) from your exhaust
can get into your vehicle as well as dirt and water.
See “Carbon Monoxide” underEngine Exhaust
on page 132.Safety Chains
You should always attach chains between your
vehicle and your trailer. Cross the safety
chains under the tongue of the trailer to help
prevent the tongue from contacting the road if it
becomes separated from the hitch. Instructions
about safety chains may be provided by the hitch
manufacturer or by the trailer manufacturer.
Follow the manufacturer’s recommendation for
attaching safety chains and do not attach them to
the bumper. Always leave just enough slack so
you can turn with your rig. Never allow safety
chains to drag on the ground.
Trailer Brakes
If your trailer weighs more than 1,000 lbs (450 kg)
loaded, then it needs its own brakes – and they
must be adequate. Be sure to read and follow the
instructions for the trailer brakes so you’ll be
able to install, adjust and maintain them properly.
If your vehicle has StabiliTrak
®, your trailer
brake system cannot tap into the vehicle’s
hydraulic brake system.
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Driving with a Trailer
{CAUTION:
If you have a rear-most window open and
you pull a trailer with your vehicle, carbon
monoxide (CO) could come into your
vehicle. You can not see or smell CO. It
can cause unconsciousness or death. See
Engine Exhaust on page 132. To maximize
your safety when towing a trailer:
Have your exhaust system inspected
for leaks, and make necessary repairs
before starting on your trip.
Keep the rear-most windows closed.
If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with
the fan on any speed. This will bring
fresh, outside air into your vehicle.
CAUTION: (Continued)
CAUTION: (Continued)
Do not use the climate control
setting for maximum air because it
only recirculates the air inside your
vehicle. See Climate Control System
in the Index.
Towing a trailer requires a certain amount of
experience. Before setting out for the open road,
you’ll want to get to know your rig. Acquaint
yourself with the feel of handling and braking with
the added weight of the trailer. And always
keep in mind that the vehicle you are driving is
now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connector,
lamps, tires and mirror adjustment. If the trailer has
electric brakes, start your vehicle and trailer
moving and then apply the trailer brake controller
by hand to be sure the brakes are working.
This lets you check your electrical connection at
the same time.
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