trailer CHEVROLET ASTRO 1999 Owner's Manual

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5-9
NOTICE:
If your engine catches fire because you keep
driving with no coolant, your vehicle can be
badly damaged. The costly repairs would not be
covered by your warranty.
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 ªDriving on Gradesº in the Index.If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. If you have an air conditioner and it's on, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
3. If you're in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
-- DRIVE (D).
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, pull over, stop, and park your
vehicle right away.
If there's still no sign of steam, 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.

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5-18
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.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a few
tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you'd use in a
skid. In any rear blowout, remove your foot from the
accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop
-- well off the road if possible.
If a tire goes flat, the next part shows how to use your
jacking equipment to change a flat tire safely.

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6-14
As shown in the chart, SAE 5W-30 is best for your
vehicle. However, you can use SAE 10W
-30 if it's going
to be 0F (
-18C) or above. These numbers on an oil
container show its viscosity, or thickness. Do not use
other viscosity oils, such as SAE 20W
-50.
NOTICE:
Use only engine oil with the American Petroleum
Institute Certified For Gasoline Engines
ªStarburstº 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 where the temperature falls below
-20F (-29C), consider using 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
Don't add anything to your oil. Your dealer is ready to
advise if you think something should be added.
When to Change Engine Oil
If any one of these is true for you, use the short trip/city
maintenance schedule:

Most trips are less than 5 to 10 miles (8 to 16 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).

Most trips are through dusty areas.

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 filter
every 3,000 miles (5 000 km) or 3 months
-- whichever
occurs first.

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6-20
Make sure the fresh air hose is still attached after the
filter change.
CAUTION:
Operating the engine with the air cleaner/filter
off can cause you or others to be burned. The air
cleaner not only cleans the air, it stops flame if
the engine backfires. If it isn't there, and the
engine backfires, you could be burned. Don't
drive with it off, and be careful working on the
engine with the air cleaner/filter off.
NOTICE:
If the air cleaner/filter is off, a backfire can cause
a damaging engine fire. And, dirt can easily get
into your engine, which will damage it. Always
have the air cleaner/filter in place when
you're driving.
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
regularly reaches 90F (32C) 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 fluid and filter every
50,000 miles (83 000 km).
See ªScheduled Maintenance Servicesº in the Index.

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6-21 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 fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire. 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 90F (32C).

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 180F to 200F
(82C to 93C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50F
(10C). If it's colder than 50F (10C), drive the
vehicle in THIRD (3) until the engine temperature gage
moves and then remains steady for 10 minutes. Then
follow the hot check procedures.

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6-62
Fuse/Circuit
BreakerUsage
1 Stop/Turn/Hazard Lamps,
CHMSL, Chime Module
2 Heated Mirror (Not Used)
3 Courtesy Lamps, Power Outside
Mirrors, Glove Box Lamp,
Dome Reading Lamps,
Vanity Mirror LampsFuse/Circuit
BreakerUsage
4 DRL Relay, DRL Module, Chime
Headlamp Switch, Keyless Entry,
Cluster, Overhead Console,
Interior Lamps Module
5 Rear Defogger
6 Cruise Module, Cruise Control
Switch, Electrochromic Mirror
7 Power Outlets, DLC, Subwoofer
Amplifier
8 Starter Enable Relay
9 License 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
10 Air Bag System
11 Wiper Motor, Washer Pump,
Upfitter Relay Coil

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6-63
Fuse/Circuit
BreakerUsage
12 L, M1, M2 Blower Motor, Rear
A/C Relay Coil, Front Cont.
Temp. Door Motor, HI Blower
Relay, Defogger Timer Coil
13 Cigarette Lighter, Door Lock
Switches, Dutch Door
Release Module
14 Cluster Illum, HVAC Controls,
Chime Module, Radio
Illumination, Rear Heat Switch
Illumination, Rear Wiper/Washer
Switch Illumination, Rear Liftgate
Switch Illumination, Remote
Cassette Illumination,
O/H Console
15 DRL Lamps
16 Front Turn Signals, Rear Turn
Signals, Trailer Turn Signals,
Back
-up Lamps, BTSI Solenoid
17 Radio: ATC (Standby),
2000 Series (Main Feed),
Rear Seat Audio ControlsFuse/Circuit
BreakerUsage
18 VCM
-Ign 3, VCM-Brake, 4WAL,
Cruise Stepper Motor Signal
19 Radio: ATC (Main Feed),
2000 Series (Standby)
20 PRNDL/ Odometer, TCC Enable
and PWM Solenoid, Shift A
and Shift B Solenoids,
3
-2 Downshift Solenoid
21 Security
22 Not Used
23 Rear Wiper, Rear Washer Pump
24 Not Used
A (Circuit Breaker) Power Door
Lock Relay, 6
-way Power Seat,
Remote Control Door Lock
Receiver, Dutch Door Module,
Dutch Door Release
B (Circuit Breaker) Power Windows

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6-65
Fuse/Circuit
Breaker Usage
UPFITTER
-BATT Upfitter Battery Power Stud,
Trailer Wiring Harness
UPFITTER
-ACCY Upfitter Accessory Relay
Spare Not used
Fuse Puller*
Spare Not used
Spare Not used
ECM
-1B Fuel Pump Relay and Motor,
VCM, Oil Pressure
Switch/Sender
HORN Horn Relay and Horn
A/C COMP A/C Enable Relay and
Compressor
ATC Active Transfer Case
-L Van
ENG
-I Oxygen Sensors, Camshaft
Position Sensor, Mass Air Flow
Sensor, Evaporative Emission
Canister Purge Solenoid, Linear
EGR Valve Solenoid, VCM
EGR HI
IGN
-E A/C Enable Relay CoilFuse/Circuit
Breaker Usage
ECM
-I Fuel Injectors 1-6, Crankshaft
Position Sensor, VCM, Coil
Driver Module (EST)
LIGHTING Park Lamps Fuse, DRL Fuse,
Headlamp and Panel Dimmer
Switch
BATT Steering/Security Fuse, Courtesy
Fuse, ACSY CB, Stop/Hazard
Fuse, Auxiliary Power Fuse,
Cigarette Lighter Fuse, Radio
Battery Fuse
IGN A Starter Relay, Ignition Switch
IGN B Ignition Switch
ABS Electronic Brake Control
Module
A/C Blower Motor Resistor, Blower
Relay
RR HTR/AC Auxiliary Heater, A/C Relay
HTD MIR/RR
DEFOGRear Window Defogger
*A fuse puller is included in the underhood electrical
center. You will also find spare fuses.

Scheduled Maintenance
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7-5
Short Trip/City Definition
Follow the Short Trip/City Scheduled Maintenance if
any one of these conditions is true for your vehicle:

Most trips are less than 5 to 10 miles (8 to 16 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).

Most trips are through dusty areas.

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 first). Chassis
Lubrication (or 3 months, whichever occurs first). Drive
Axle Service (or 3 months, whichever occurs first).
Every 6,000 Miles (10 000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Air Cleaner Filter
Inspection, if driving in dusty conditions. Front
Wheel Bearing Repack (2WD only) (or at each brake
relining, whichever occurs first). Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Air Cleaner Filter
Replacement. Fuel Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection. Fuel Tank, Cap and
Lines Inspection.

Scheduled Maintenance
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7-6
Short Trip/City Intervals
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 first).
These intervals only summarize maintenance services.
Be sure to follow the complete scheduled maintenance
on the following pages.
Long Trip/Highway Definition
Follow this scheduled maintenance only if none of the
conditions from the Short Trip/City Scheduled
Maintenance is 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 causes engine oil to break
down slower.