engine CHEVROLET ASTRO CARGO VAN 2004 2.G Service Manual

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 inless 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.
4-21

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.
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.
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.
{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 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.
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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 ashers.
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 have no blankets or extra clothing, make
body insulators from newspapers, burlap bags, rags,
oor 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 can not 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. 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.
4-27

If You Are 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 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 your wheels can destroy parts
of your vehicle as well as the tires. If you spin the
wheels too fast while shifting your transmission
back and forth, you can destroy your transmission.
For information about using tire chains on your
vehicle, seeTire Chains on page 5-76.
Rocking Your Vehicle To Get It Out
First, turn your steering wheel left and right. That will
clear the area around your 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 your wheels in the forward
and reverse directions, you will cause a rocking
motion that may free your vehicle. If that does not get
you out after a few tries, you may need to be towed out.
If you do need to be towed out, seeTowing Your
Vehicle on page 4-29.
4-28

Towing a Trailer
{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. Pull a trailer only if you have
followed all the steps in this section. Ask your
dealer 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 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.If yours was built with trailering options, as many are,
it’s ready for heavier trailers. But trailering is different
than just driving your vehicle by itself. Trailering means
changes in handling, acceleration, braking, 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.
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 rst 500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
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Then, during the rst 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, and
improve control of vehicle speed while requiring
less throttle pedal activity.Press the button on the end of the shift lever 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 3-34.
Tow/haul is most effective when the vehicle and trailer
combined weight is at least 75% 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. And, it can also
depend on any special equipment that you have
on your vehicle.
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Hitches
It’s important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads
are a few reasons why you’ll need the right hitch.
Weight-Distributing Hitches and Weight
Carrying Hitches
When using a weight-distributing hitch, the hitch
must be adjusted so that the distance (A) remains the
same both before and after coupling the trailer to the
tow vehicle.If you use a step-bumper hitch, your bumper could be
damaged in sharp turns. Make sure you have ample
room when turning to avoid contact between the trailer
and the bumper.
If you’ll be pulling a trailer that, when loaded, will weigh
more than 2,000 lbs. (900 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 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 2-29. (A) Body to Ground Distance, (B) Front of Vehicle
4-39

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. SeeEngine
Exhaust on page 2-29. 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. 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 the trailer hitch and platform
(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.
During your trip, check occasionally to be sure that
the load is secure, and that the lamps and any trailer
brakes are still working.
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