tow CHEVROLET ASTRO 2003 Service Manual

Driving with a Trailer
If you ~ ve a rear-most window open and
you pull a trailer with your vehicle, carbon monoxide (CO) could come into your vehicle.
You can’t see or smell
CO. It can cause
unconsciousness or death. See “Engine
Exhaust” in the Index.
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 Controls” 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.
4-37

Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving your vehicle without a trailer.
This can help you avoid situations that require
heavy braking and sudden turns.
Passing
You’ll need more passing distance up ahead when
you’re towing a trailer. And, because you’re a good deal
longer, you’ll need to go much farther beyond the
passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, just move that hand
to the left.
To move the trailer to the right, move your
hand to the right. Always back up slowly and,
if possible,
have someone guide you.
Making Turns
Notice: Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns than
normal.
Do this so your trailer won’t strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have extra
wiring (included in the optional trailering package).
The arrows on your instrument panel will flash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also flash, telling other drivers
you’re about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will flash for turns even
if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It’s
important to check occasionally to be sure the trailer
bulbs are still working.
4-38

Driving On Grades Parking on Hills
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade.
If you don’t shift
down, you might have to use your brakes
so much that
they would get hot and no longer work well.
You can tow in DRIVE (D). You may want to shift the
transmission to THIRD
(3) or, if necessary, a lower gear
selection
if the transmission shifts too often (e.g., under
heavy loads and/or hilly conditions).
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 you turn your
engine
off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating.
To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK
(P) for a
few minutes before turning the engine
off. If you do get
the overheat warning, see
Engine Overheating on
page
5-3 1.
You really shoul tot park your vehicle, ith a
trailer attached, on a hill.
If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
2. Have someone place chocks under the trailer
3. When the wheel chocks are in place, release the
4. Reapply the regular brakes. Then apply your PARK (P) yet.
wheels. regular brakes until the chocks absorb the load.
parking brake, and shift to PARK (P).
5. Release the regular brakes.
4-39

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission fluid (don’t overfill),
engine oil, axle lubricant, belt, cooling system and
brake system. Each
of these is covered in this manual,
and the Index will help you find them quickly.
If you’re
trailering, it’s a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
4-40

A. Windshield Washer Fluid
B. Engine Coolant
C. Engine
Oil Dipstick
D. Transmission Dipstick
E. Engine Air Cleaner/Filter
F. Engine Oil Fill
G. Brake Master Cylinder Reservoir
H. Power Steering Fluid Reservoir
I. Battery
Engine Oil
It is important to keep engine oil at the proper level. The engine oil dipstick has a yellow ring and is located
near the center of the engine compartment. See
Engine
information on location.
Checking Engine Oil Compartment Overview on page 5- 14 for more
It’s a good idea to check your engine oil every time
you
get fuel. In order to get an accurate reading, the oil Turn off the engine and give the oil several minutes to
must be warm and the vehicle must be on level ground. drain back into the
Oil pan. If YOU don’t, the oil dipstick
might not show the actual level.
Pull out the dipstick and clean it with a paper towel or
cloth, then push it back in all the way. Remove it again,
keeping the tip down, and check the level.
5-1 5

As in the chart shown previously, SAE 5W-30 is the
only viscosity grade recommended for your vehicle.
You should look for and use only oils which have the
API Starburst symbol and which are also identified
as SAE 5W-30.
If you cannot find such SAE 5W-30 oils,
you can use an SAE IOW-30 oil which has the API
Starburst symbol,
if it's going to be 0°F (-18°C)
or above.
Do not use other viscosity grade oils, such as
SAE 1OW-40 or SAE 20W-50 under any conditions.
Notice: Use only engine oil with the American
Petroleum Institute Certified For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.
GM Goodwrench@ oil meets all the requirements for
your vehicle.
If you are in an area of extreme cold, where the
temperature falls below -20°F (-29"C), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE OW-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Don't add anything to your oil. The recommended oils
with the starburst symbol are all you will need for
good performance and engine protection.
When to Change Engine Oil
If any one of these are true for you, use the short
tripkity maintenance schedule:
e
e
e
Most trips are less than 5 miles (8 km). This is
particularly important when outside temperatures
are below freezing.
Most trips include extensive idling (such as frequent
driving in stop-and-go traffic).
You frequently tow a trailer or use a carrier on top
of your vehicle.
The vehicle is used for delivery service, police, taxi
or other commercial application.
5-1
8

Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every
15,000 miles
(25
000 km) if the vehicle is mainly driven under one or
more of these conditions:
In heavy city traffic where the outside temperature
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery
If you do not use your vehicle under any of these
conditions, change the fluid and filter every
50,000 miles (83 000 km).
See
Part A: Scheduled Maintenance Services on
page
6-4.
regularly reaches 90°F (32°C) or higher.
service.
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notices Too much or too little fluid can damage
your transmission.
Too much can mean that some
of the fluid could come out and fall on hot engine
part or exhaust system parts, starting a fire.
Too little fluid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level
if you have been driving:
When outside temperatures are above 90°F (32°C).
0 At high speed for quite a while.
In heavy traffic
- especially in hot weather.
While pulling a trailer.
To get the right reading, the fluid should be at normal
operating temperature, which is 180°F to 200°F
(82°C to 93°C).
5-25

Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50°F
(10°C).
If it's colder than 50°F (IOOC), drive the vehicle
in THIRD
(3) until the engine temperature gage
moves and then remains steady for
10 minutes.
A cold fluid check can be made after the vehicle has
been sitting for eight hours or more with the engine
off,
but this is used only as a reference. Let the engine
run at idle for five minutes
if outside temperatures are
50°F (1 OOC) or more.
If it's colder than 50°F (IOOC), you may have to idle the
engine longer. Should the fluid level be low during
this cold check, you
must check the fluid hot before
adding fluid. Checking the fluid hot
will give you a more
accurate reading of the fluid level.
Checking the Fluid Level
Prepare your vehicle as follows:
Park your vehicle on a level place. Keep the engine
running.
With the parking brake applied, place the shift lever
in PARK (P).
With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK
(P).
Let the engine run at idle for three minutes or more. Then, without
shutting
off the engine, follow these steps:
The transmission dipstick has a red handle and is
located near the center of the engine compartment
behind the air cleaner. See
Engine Compartment
Overview on page 5-14
for more information on location.
1. Flip the handle up and then pull out the dipstick
and wipe it with a clean rag or paper towel.
2. Push it back in all the way, wait three seconds and
then pull
it back out again.
5-26

If No Steam Is Coming From
Your Engine
If you get an engine overheat warning but see or
hear no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. See ”Driving on Grades” in Towing a
Trailer on page 4-3 I.
If you get the overheat warning with no sign of steam,
try this for a minute or
so:
1. In heavy traffic, let the engine idle in NEUTRAL (N)
while stopped. If it is safe to do so, pull off the road,
shift to PARK (P) or NEUTRAL
(N) and let the
engine idle.
If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about
10 minutes.
If the warning doesn’t come back on, you can drive
normally.
If the warning continues and you have not stopped,
pull over, stop, and park your vehicle right away.
If there’s still no sign of steam, you can push down the
accelerator until the engine speed is about twice as
fast as normal idle speed for at least three minutes while
you’re parked. If you still have the warning’turn
off the
engine and get everyone
out of the vehicle until it cools
down.
You may decide not to lift the hood but to get service
help right away.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
5-32

6. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fan.
7. By this time, the coolant level inside the radiator
filler neck may be lower.
If the level is lower, add
more of the proper
DEX-COOL@ coolant mixture
through the filler neck until the level reaches
the base of the filler neck.
Then replace the pressure cap. At any time during
this procedure
if coolant begins to flow out of
the filler neck, reinstall the pressure cap. Be sure
the arrow on the pressure cap lines up.
Engine Fan Noise
This 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 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 when the clutch
engages.
So you may hear an increase in fan noise.
This is normal and should not be mistaken as the
transmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
5-39