towing CHEVROLET ASTRO 2004 Owner's Manual

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 ¯uid (don't over®ll),
engine oil, axle lubricant, belt, cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you ®nd 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.
Trailer Wiring Harness
If you have the optional trailering package, your vehicle
will have an eight-wire harness, including the center
high-mounted stoplamp battery feed wire. The harness
is stored on the passenger's side of the vehicle near
the rear wheel well. This harness has a 30 amp battery
feed wire and no connector, and should be wired by
a quali®ed electrical technician. After choosing an
aftermarket trailer mating connector pair, have the
technician attach one connector to the eight-wire trailer
harness and the other connector to the wiring harness
on the trailer. Be sure the wiring harness on the trailer is
taped or strapped to the trailer's frame rail and leave
it loose enough so the wiring doesn't bend or break, but
not so loose that it drags on the ground. The eight-wireharness must be routed out of your vehicle between the
rear door and the ¯oor, with enough of the harness
left on both sides so that the trailer or the body won't pull
it. If you do not have the optional trailering package,
your vehicle will still have a trailering harness. The
harness is located near the passenger's side rear wheel
well. It consists of six wires that may be used by
after-market trailer hitch installers.
The technician can use the following color code chart
when connecting the wiring harness to your trailer.
·Brown: Rear lamps.
·Yellow: Left stoplamp and turn signal.
·Dark Green: Right stoplamp and turn signal.
·White (Heavy Gage): Ground.
·Light Green: Back-up lamps.
·White (Light Gage): Center High-Mounted Stoplamp.
·Blue: Auxiliary circuit (eight-wire harness only).
·Orange: Fused auxiliary (eight-wire harness only).
Store the harness in its original place. Wrap the
harness together and tie it neatly so it won't
be damaged.
4-44

How to Inspect the Engine Air
Cleaner/Filter
To inspect the engine air cleaner/®lter remove the ®lter
from the vehicle and lightly shake ®lter to release
loose dust and dirt. If the ®lter remains caked with dirt, a
new ®lter is required.
To inspect or replace the ®lter, do the following:
1. Unsnap both clips on the cover.
2. Remove the cover.
3. Change the ®lter.
4. Snap both clips to secure the engine air
cleaner/®lter cover.
{CAUTION:
Operating the engine with the air cleaner/®lter
off can cause you or others to be burned. The
air cleaner not only cleans the air, it helps to
stop ¯ame if the engine back®res. If it is not
there and the engine back®res, you could
be burned. Do not drive with it off, and be
careful working on the engine with the air
cleaner/®lter off.
Notice:If the air cleaner/®lter is off, a back®re can
cause a damaging engine ®re. And, dirt can
easily get into your engine, which will damage it.
Always have the air cleaner/®lter in place when you
are driving.
Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission ¯uid
level is when the engine oil is changed.
Change both the ¯uid and ®lter 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
regularly reaches 90ÉF (32ÉC) or higher.
·In hilly or mountainous terrain.
·When doing frequent trailer towing.
·Uses such as found in taxi, police or delivery
service.
If you do not use your vehicle under any of these
conditions, change the ¯uid and ®lter every 50,000 miles
(83 000 km).
See
Part A: Scheduled Maintenance Services on
page 6-4.
5-22

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. See²Driving on Gradesº inTowing a
Trailer on page 4-35
.
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.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.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 vehicleuntil it
cools down.
You may decide not to lift the hood but to get service
help right away.
5-29

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
®ller neck may be lower. If the level is lower, add
more of the proper DEX-COOL
žcoolant mixture
through the ®ller neck until the level reaches
the base of the ®ller neck.
Then replace the pressure cap. At any time during
this procedure if coolant begins to ¯ow out of
the ®ller 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.
5-36

Long Trip/Highway De®nition
Follow this scheduled maintenanceonlyif none of the
conditions from the Short Trip/City Scheduled
Maintenance are true. Do not use this schedule if the
vehicle is used for trailer towing, driven in a dusty area
or used off paved roads. Use the Short Trip/City
schedule for these conditions
Driving a vehicle with a fully warmed engine under
highway conditions will cause engine oil to break down
slower.
Long Trip/Highway Intervals
Every 7,500 Miles (12 500 km):Engine Oil and Filter
Change (or every 12 months, whichever occurs
®rst). Chassis Lubrication (or 12 months, whichever
occurs ®rst). Drive Axle Fluid Check. Tire Rotation.
Every 15,000 Miles (25 000 km):Engine Air Cleaner
Filter Inspection. Automatic Transmission Service
(severe conditions only).
Every 30,000 Miles (50 000 km):Fuel Filter
Replacement. Engine Air Cleaner Filter Replacement.
Front Wheel Bearing Repack (two±wheel drive only) (or
at each brake relining, whichever occurs ®rst).
Every 50,000 Miles (83 000 km):Automatic
Transmission Service (normal conditions). Transfer
Case Fluid Change.Every 100,000 Miles (166 000 km):Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km):Cooling System
Service (or every 60 months, whichever occurs
®rst). Engine Accessory Drive Belt Inspection.
These intervals only summarize maintenance services.
Be sure to follow the complete scheduled maintenance
on the following pages.
Short Trip/City Scheduled
Maintenance
The services shown in this schedule up to 100,000 miles
(166 000 km) should be repeated after 100,000 miles
(166 000 km) at the same intervals for the life of
this vehicle. The services shown at 150,000 miles
(240 000 km) should be repeated at the same interval
after 150,000 miles (240 000 km) for the life of this
vehicle.
See
Part B: Owner Checks and Services on page 6-24andPart C: Periodic Maintenance Inspections on
page 6-28.
6-6

15,000 Miles (25 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qInspect engine air cleaner ®lter. If necessary, replace
the ®lter. If vehicle is driven in dusty/dirty conditions,
inspect ®lter at every engine oil change. See
Engine Air Cleaner/Filter on page 5-20for more
information.An Emission Control Service. (See
footnote ².)
qFor Two-Wheel-Drive vehicles only: Clean and
repack the front wheel bearings (or at each
brake relining, whichever occurs ®rst).
qChange automatic transmission ¯uid and ®lter if the
vehicle is mainly driven under one or more of these
conditions:
þ In heavy city traffic where the outside
temperature regularly reaches 90ÉF (32ÉC) or
higher.
þ In hilly or mountainous terrain.
þ When doing frequent trailer towing.
þ Uses such as found in taxi, police or delivery
service.
If you do not use your vehicle under any of these
conditions, change the ¯uid and ®lter every 50,000 miles
(83 000 km).
18,000 Miles (30 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
21,000 Miles (35 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
24,000 Miles (40 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
6-8

27,000 Miles (45 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
30,000 Miles (50 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qFor Two-Wheel-Drive vehicles only: Clean and
repack the front wheel bearings (or at each
brake relining, whichever occurs ®rst).
qReplace fuel ®lter.
An Emission Control Service. (See
footnote ².)
qReplace engine air cleaner ®lter. SeeEngine Air
Cleaner/Filter on page 5-20for more information.An Emission Control Service.
qChange automatic transmission ¯uid and ®lter if the
vehicle is mainly driven under one or more of these
conditions:
þ In heavy city traffic where the outside
temperature regularly reaches 90ÉF (32ÉC) or
higher.þ In hilly or mountainous terrain.
þ When doing frequent trailer towing.
þ Uses such as found in taxi, police or delivery
service.
If you do not use your vehicle under any of these
conditions, change the ¯uid and ®lter every 50,000 miles
(83 000 km).
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
33,000 Miles (55 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
36,000 Miles (60 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
6-9

39,000 Miles (65 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
42,000 Miles (70 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
45,000 Miles (75 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qFor Two-Wheel-Drive vehicles only: Clean and
repack the front wheel bearings (or at each
brake relining, whichever occurs ®rst).qChange automatic transmission ¯uid and ®lter if the
vehicle is mainly driven under one or more of these
conditions:
þ In heavy city traffic where the outside
temperature regularly reaches 90ÉF (32ÉC) or
higher.
þ In hilly or mountainous terrain.
þ When doing frequent trailer towing.
þ Uses such as found in taxi, police or delivery
service.
qInspect engine air cleaner ®lter. If necessary, replace
the ®lter. If vehicle is driven in dusty/dirty conditions,
inspect ®lter at every engine oil change. See
Engine Air Cleaner/Filter on page 5-20for more
information.An Emission Control Service. (See
footnote ².)
If you do not use your vehicle under any of these
conditions, change the ¯uid and ®lter every 50,000 miles
(83 000 km).
48,000 Miles (80 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
6-10

60,000 Miles (100 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qFor Two-Wheel-Drive vehicles only: Clean and
repack the front wheel bearings (or at each
brake relining, whichever occurs ®rst).
qChange automatic transmission ¯uid and ®lter if the
vehicle is mainly driven under one or more of these
conditions:
þ In heavy city traffic where the outside
temperature regularly reaches 90ÉF (32ÉC) or
higher.
þ In hilly or mountainous terrain.
þ When doing frequent trailer towing.
þ Uses such as found in taxi, police or delivery
service.
If you do not use your vehicle under any of these
conditions, change the ¯uid and ®lter every 50,000 miles
(83 000 km).
qReplace fuel ®lter.An Emission Control Service. (See
footnote ².)
qReplace engine air cleaner ®lter. SeeEngine Air
Cleaner/Filter on page 5-20for more information.An Emission Control Service.
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
63,000 Miles (105 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
66,000 Miles (110 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
6-12

69,000 Miles (115 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
72,000 Miles (120 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
75,000 Miles (125 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qFor Two-Wheel-Drive vehicles only: Clean and
repack the front wheel bearings (or at each
brake relining, whichever occurs ®rst).qChange automatic transmission ¯uid and ®lter if the
vehicle is mainly driven under one or more of these
conditions:
þ In heavy city traffic where the outside
temperature regularly reaches 90ÉF (32ÉC) or
higher.
þ In hilly or mountainous terrain.
þ When doing frequent trailer towing.
þ Uses such as found in taxi, police or delivery
service.
If you do not use your vehicle under any of these
conditions, change the ¯uid and ®lter every 50,000 miles
(83 000 km).
qInspect engine air cleaner ®lter. If necessary, replace
the ®lter. If vehicle is driven in dusty/dirty conditions,
inspect ®lter at every engine oil change. See
Engine Air Cleaner/Filter on page 5-20for more
information.An Emission Control Service. (See
footnote ².)
78,000 Miles (130 000 km)
qChange engine oil and ®lter (or every 3 months,
whichever occurs ®rst).An Emission Control Service.
qLubricate chassis components (or every 3 months,
whichever occurs ®rst).(See footnote #.)
qRotate tires. SeeTire Inspection and Rotation on
page 5-62for proper rotation pattern and additional
information.(See footnote +.)
6-13