heater CHEVROLET ASTRO 1999 User Guide

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4-27
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't 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
doesn't collect there.
Open a window just a little on the side of the
vehicle that's 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.
Recreational Vehicle Towing
Your vehicle was not designed to be towed with all four
wheels on the ground. If your vehicle must be towed,
see ªTowing Your Vehicleº in the Index.
NOTICE:
Towing your vehicle with all four wheels on the
ground will damage drivetrain components.

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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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5-10
Cooling System
When you decide it's safe to lift the hood, here's what
you'll see:
A. Coolant Recovery Tank
B. Radiator Pressure Cap
C. Engine Fan
If the coolant inside the coolant recovery tank is boiling,
don't do anything else until it cools down.
The coolant level should be at the ADD mark. If it
isn't, you may have a leak in the radiator hoses, heater
hoses, radiator, water pump or somewhere else in the
cooling system.

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5-11
CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Don't touch them. If you
do, you can be burned.
Don't run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
NOTICE:
Engine damage from running your engine
without coolant isn't covered by your warranty.
NOTICE:
When adding coolant, it is important that you use
only DEX
-COOL
(silicate-free) coolant.
If coolant other than DEX-COOL is added to the
system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
-- at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the use
of coolant other than DEX
-COOL
is not
covered by your new vehicle warranty.

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5-13
NOTICE:
In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot
enough. Don't spill coolant on a hot engine.
When the coolant in the coolant recovery tank is at the
ADD mark, start your vehicle.
If the overheat warning continues, there's one more
thing you can try. You can add the proper coolant
mixture directly to the radiator, but be sure the cooling
system is cool before you do it.

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6-17
4. Disconnect the electrical connectors and set the
extension aside.5. Grasp the top of the heater duct and pull down gently
to remove it.

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6-19 Installing the Engine Cover
1. Lift the engine cover into the vehicle and slide it all
the way forward. Make sure the rubber seal is over
the latches.
2. Install the two bolts at the engine cover.
3. Put the heater duct over the engine cover studs. Push
up on the duct gently until it snaps into place.
4. Reconnect the electrical connectors.
5. Install the engine cover extension by gently
squeezing the sides and sliding it into place. Make
sure all of the fastener clips engage and the extension
fits properly in place. Replace and tighten the
two screws.
6. Install the two nuts to secure the extension in place.
Engine Air Cleaner/Filter
Refer to the Maintenance Schedule to determine when to
replace the air filter and the crankcase ventilation filter.
See ªScheduled Maintenanceº in the Index.
To remove the air filter, lift the hood, unsnap both clips
and remove the top. After changing the filter, snap both
clips to secure the air cleaner. Be sure the air cleaner lid
is correctly positioned to seal out dust and contaminants
that are harmful to your engine.

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6-27
Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant system. The thermostat stops the
flow of coolant through the radiator until the coolant
reaches a preset temperature.
Engine Coolant
The cooling system in your vehicle is filled with
DEX
-COOL
engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX
-COOL
extended life coolant.
The following explains your cooling system and how
to add coolant when it is low. If you have a problem
with engine overheating, see ªEngine Overheatingº in
the Index.A 50/50 mixture of clean, drinkable water and
DEX
-COOL
coolant will:

Give freezing protection down to
-34F (-37C).

Give boiling protection up to 265F (129C).

Protect against rust and corrosion.

Help keep the proper engine temperature.

Let the warning lights and gages work as
they should.
NOTICE:
When adding coolant, it is important that you
use only DEX
-COOL (silicate-free) coolant.
If coolant other than DEX-COOL is added to
the system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
-- at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the
use of coolant other than DEX
-COOL is not
covered by your new vehicle warranty.

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6-28 What to Use
Use a mixture of one-half clean, drinkable water and
one
-half DEX-COOL
coolant which won't damage
aluminum parts. If you use this coolant mixture, you
don't need to add anything else.
CAUTION:
Adding only plain water to your cooling system
can be dangerous. Plain water, or some other
liquid like alcohol, can boil before the proper
coolant mixture will. Your vehicle's coolant
warning system is set for the proper coolant
mixture. With plain water or the wrong mixture,
your engine could get too hot but you wouldn't
get the overheat warning. Your engine could
catch fire and you or others could be burned.
Use a 50/50 mixture of clean, drinkable water
and DEX
-COOL
coolant.
NOTICE:
If you use an improper coolant mixture, your
engine could overheat and be badly damaged.
The repair cost wouldn't be covered by your
warranty. Too much water in the mixture can
freeze and crack the engine, radiator, heater core
and other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
NOTICE:
If you use the proper coolant, you don't have to
add extra inhibitors or additives which claim to
improve the system. These can be harmful.

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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.