1996 CHEVROLET EXPRESS cooling

Downloaded from www.Manualslib.com manuals search engine A 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.
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 FULL COLD mark, add a 5060 mixture of
clean water (preferably distilled) and DEX-COOL’”
(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 sy,,,m
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.
c 11

Downloaded from www.Manualslib.com manuals search engine I 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.
A CAIJTION:
-
You can be b ed 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
FULL COLD 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.
5-14

Downloaded from www.Manualslib.com manuals search engine 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 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.
5-15

Downloaded from www.Manualslib.com manuals search engine 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
pressure cap.)
If you hear a hiss, wait for that to stop. A hiss means
there is still some pressure left.
2. Then keep turning the pressure cap, but now push
down as you turn it. Remove the pressure cap.
5-16

Downloaded from www.Manualslib.com manuals search engine 8. Then replace the pressure cap. At any time during
this procedure
if coolant begins to flow out of the
filler neck, reinstall the pressure cap. Be sure the
arrows
on the pressure cap line up like this.
Engine Fan Noise
Your 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 fan
is spinning slower and 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
as the clutch
more
fully 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 partially disengages.
You may also hear this Fan noise when you start
the engine. It will go away as the fan clutch
partially disengages.
5-19

Downloaded from www.Manualslib.com manuals search engine Engine Coolant
The cooling system in your vehicle is filled with new
DEX-COOL
TM (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 5060 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 ( 129 O C).
Protect against rust and corrosion.
0 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
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.
6-20

Downloaded from www.Manualslib.com manuals search engine What to Use
Use a mixture of one-half
clean water (preferably
distilled) and one-half DEX-COOL
Rul (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.
’/d 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 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 (orange-colored,
silicate-free) antifreeze.
6-21

Downloaded from www.Manualslib.com manuals search engine 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 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.
Checking Coolant
When your engine is cold, the coolant level should be at
FULL COLD, or a little higher.
6-22