1996 CHEVROLET ASTRO cooling

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.
Engine damage from running your engine without coolant isn’t covered by your warranty.
If there seems to be
no leak, start the engine again. See
if the fan speed increases when idle speed
is doubled by
pushing the accelerator pedal down.
If it doesn’t, your
vehicle needs service. Turn off the engine.
How to Add Coolant to the Coolant
Recovery Tank
If you haven’t found a problem yet, but the coolant level
isn’t at the
ADD mark, add a 50/50 mixture of clean
water (preferably distilled) and DEX-COOL TM
(orange-colored, silicate-free) antifreeze at the coolant
recovery tank. (See “Engine Coolant’’
in the Index for
more information.)
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 mix
will. Your vehicle’s coolant warning
system is set
for the proper coolant mix. With
plain water or the wrong mix, 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 mix of clean
water and
DEX-COOL TM antifreeze.
5-16

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 mix.
I A 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 mix
directly
to the radiator, but be sure the cooling system is
cool before you do
it.

Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the radiator
pressure cap
-- even a little -- they can come out
at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap,
is hot. Wait for the cooling system and
radiator pressure cap to cool if you ever have to
turn the pressure cap.

How to Add Coolant to the Radiator
1. You can remove the
radiator pressure cap
when the cooling
system, including the
radiator pressure cap and
upper radiator hose, is
no longer hot. Turn the
pressure cap slowly
counterclockwise until it
first stops. (Don't press
down while turning the
If
you hear a hiss, wait for that to stop. A hiss means
there is still some pressure left.
I 2. Then keep turning
I ,the pressure cap, but
now push down as you
5-19

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 every day 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 “blow out” 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 4‘blowout,” 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.
5-22

What to Use Rear Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when
to change it. See
“Scheduled Maintenance Services” in the Index.
How to Check Lubricant
If the level is below the bottom of the filler plug hole,
you’ll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of the filler plug hole. Refer
to the Maintenance Schedule to determine what
kind of lubricant
to use. See “Recommended Fluids and
Lubricants” in the Index.
Engine Coolant
The cooling system in your vehicle is filled with new
DEX-COOL (orange-colored, silicate-free) engine
coolant. This coolant is designed to remain in your
vehicle for
5 years or 100,000 miles (166 000 km),
whichever occurs first.
The following explains your cooling system and how to
add coolant when it is low. If
you have a problem with
engine overheating, see “Engine Overheating’’ in
the Index.
A 50/50 mixture of water and the proper coolant for
your vehicle will:
0 Give freezing protection down to -34°F (-37°C).
Give boiling protection up to 265 “F (1 29°C).
0 Protect against rust and corrosion.
Help keep the proper engine temperature.
0 Let the warning lights and gages work as
they should.
6-25

NOTICE:
When adding coolant it is important that you use
DEX-COOL
TM (orange-colored, silicate-free)
coolant meeting
GM Specification 6277M.
If silicated coolant 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.
What to Use
Use a mixture
of one-half clean water (preferably
distilled) and one-half
DEX-COOL (orange-colored,
silicate-free) antifreeze that meets GM Specification
6277M, which won’t damage aluminum parts. Use GM
Engine Coolant Supplement (sealer)
(GM Part
No. 3634621) with any complete coolant change. If you
use this mixture, you don’t need to add anything else.
A CAUTION:
I
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 mix will. Your vehicle’s coolant warning
system is set for the proper coolant mix. With
plain water or the wrong mix, 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 mix of clean
water and DEX-COOL (orange-colored,
silicate-free) antifreeze.
6-26

NOTICE:
If you use an improper coolant mix, your engine
could overheat and be badly damaged. The repair
cost wouldn’t be covered by your warranty. Too
much water in the mix can freeze and crackthe
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.
I NOTICE: I
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.
Checking Coolant
When your engine is cold, the coolant level should be at
ADD, or a little higher. When your engine is warm, the
level should be up to
FULL HOT, or a little higher.
6-27