2004 CHEVROLET ASTRO CARGO VAN trailer

You should look for this information on the oil container,
and useonlythose oils that are identied as meeting
GM Standard GM6094M and have the starburst symbol
on the front of the oil container.
Notice:Use only engine oil identied as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certied 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 0W-30 oil. Both will provide
easier cold starting and better protection for your
engine at extremely low temperatures.
Engine Oil Additives
Do not add anything to your oil. The recommended
oils with the starburst symbol that meet GM Standard
GM6094M 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
trip/city maintenance schedule:
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.
Driving under these conditions causes engine oil to
break down sooner. If any one of these is true for your
vehicle, then you need to change your oil and lter
every 3,000 miles (5 000 km) or 3 months – whichever
occurs rst.
If none of them is true, use the long trip/highway
maintenance schedule. Change the oil and lter every
7,500 miles (12 500 km) or 12 months – whichever
occurs rst. Driving a vehicle with a fully warmed engine
under highway conditions will cause engine oil to
break down slower.
5-16

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 90°F (32°C) 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).
SeePart A: Scheduled Maintenance Services
on page 6-4.
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.
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
part or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if
you check your transmission uid.
Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should be
at normal operating temperature, which is
180°F to 200°F (82°C to 93°C).
5-23

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” under
Towing 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 does not 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 is 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 are 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.
5-30

3
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
®coolant 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.
5-37

Fuse/Circuit
BreakerUsage
1Stop/Turn/Hazard Lamps,
Center High Mounted Stop Lamp,
Anti-Lock Brakes
2Radio Accessory, Rear Seat
Audio Controls
Fuse/Circuit
BreakerUsage
3Courtesy Lamps, Glove Box Lamp,
Dome Reading Lamps, Vanity
Mirror Lamps, Courtesy Lamps
4Daytime Running Lamps Relay,
Instrument Panel Cluster
5 Rear Defogger
6Cruise Module, Truck Body
Control Module, Instrument Panel
Cluster, Cruise Control Switch,
Electrochromic Mirror
7 Power Outlets, Subwoofer Amplier
8Crank Circuit Fuse, Park/Neutral
Switch, Starter Enabler Relay
9License Plate Lamp, Taillamps,
Parking Lamps, Ashtray Lamp,
Panel Lights, Trailer Taillamps,
Front and Rear Sidemarker
Lamps, Door Switch Illumination,
Headlamp Switch Illumination,
Rear Seat Audio Illumination,
Truck Body Control Module
10 Air Bag System
5-102

Fuse/Circuit
BreakerUsage
11 Not Used
12Blower Motor, Rear Air Conditioning
Relay Coil, Front Cont. Temp.
Door Motor, HI Blower Relay,
Defogger Timer Coil
13Cigarette Lighter, Door Lock
Switches, Dutch Door
Release Module
14Cluster Illumination, Climate
Controls, Chime Module, Radio
Illumination, Rear Heat Switch
Illumination, Rear Wiper/Washer
Switch Illumination, Rear Liftgate
Switch Illumination, Remote
Cassette Illumination,
Overhead Console, Truck Body
Control Illumination
15Truck Body Module,
Headlamp Relay
16Front Turn Signals, Rear
Turn Signals, Trailer Turn
Signals, Back-Up Lamps,
Brake Transmission Shift
Interlock SolenoidFuse/Circuit
BreakerUsage
17 Front Wipers, Front Washer Pump
18VCM-Ign 3, VCM-Brake,
Cruise Stepper Motor Signal,
ATC Module
19Instrument Panel Radio: ATC
(Main Feed), 2000 Series (Standby)
20PRNDL/Odometer, Shift A and
Shift B Solenoids, 3–2 Downshift
Solenoid, Instrument Panel Cluster,
VCM Module
21 Powr Adjust Mirrors
22 Not Used
23 Rear Wiper, Rear Washer Pump
24 Not Used
A(Circuit Breaker) Power Door
Lock Relay, 6–Way Power Seats
B (Circuit Breaker) Power Windows
5-103

Relays Usage
A/C Relay
(Rear Heat
and A/C)Rear/Heat and Air Conditioning
Uptter-ACCY
RelayUptter Accessory
Starter Enable
RelayStarter
A/C Enable
RelayAir Conditioning
Headlamps
RelayHeadlamps
Fuel Pump
RelayFuel PumpFuse/Circuit
BreakerUsage
UPFITTER-
BATTUptter Battery Power Stud,
Trailer Wiring Harness
UPFITTER-
ACCYUptter Accessory Relay
Spare Not used
Spare Not used
Spare Not used
ECM-1BFuel Pump Relay and Motor,
VCM, Oil Pressure Switch/Sender
HORN Horn Relay and Horn
A/C COMPAir Conditioning Enable Relay
and Compressor
RR HTR/AC Rear Heater and Air Conditioning
ATC Active Transfer Case-L Van
FRT HVAC Front Heater and Air Conditioning
5-105

Selecting the Right Schedule
First you will need to decide which of the two schedules
is right for your vehicle. Here is how to decide which
schedule to follow:
Short Trip/City Denition
Follow the Short Trip/City Scheduled Maintenance if any
one of these conditions is true for your vehicle:
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.
If the vehicle is used for delivery service, police,
taxi or other commercial application.
One of the reasons you should follow this schedule if
you operate your vehicle under any of these conditions
is that these conditions cause engine oil to break
down sooner.
Short Trip/City Intervals
Every 3,000 Miles (5 000 km):Engine Oil and
Filter Change (or 3 months, whichever occurs rst).
Chassis Lubrication (or 3 months, whichever occurs
rst). Drive Axle Fluid Check.
Every 6,000 Miles (10 000 km):Tire Rotation.
Every 15,000 Miles (25 000 km):Engine Air Cleaner
Filter Inspection. Front Wheel Bearing Repack
(two–wheel drive only) (or at each brake relining,
whichever occurs rst). Automatic Transmission
Service (severe conditions only).
Every 30,000 Miles (50 000 km):Engine Air Cleaner
Filter Replacement. Fuel Filter Replacement.
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.
6-5