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When the engine is cold, the coolant level should
be at or above the COLD FILL mark. If it is
not, you may have a leak at the pressure cap or in
the radiator hoses, heater hoses, radiator, water
pump, or somewhere else in the cooling system.
{CAUTION:
Heater, fuel operated heater (FOH),
radiator hoses, and other engine parts,
can be very hot. Do not touch them.
If you do, you can be burned.
Do not run the engine if there is a leak.
If you run the engine, it could lose all
coolant. That could cause an engine re,
and you could be burned. Get any leak
xed before you drive the vehicle.
If there seems to be no leak, start the engine
again. See if the engine cooling fan speed
increases when idle speed is doubled by pushing
the accelerator pedal down. If it does not, your
vehicle needs service. Turn off the engine.Notice:Engine damage from running your
engine without coolant is not covered by
your warranty.
Notice:Using coolant other than DEX-COOL
®
may cause premature engine, heater core, or
radiator corrosion. In addition, the engine
coolant could require changing sooner, at
30,000 miles (50 000 km) or 24 months,
whichever occurs rst. Any repairs would
not be covered by your warranty. Always
use DEX-COOL
®(silicate-free) coolant in
your vehicle.
How to Add Coolant to the Coolant
Recovery Tank for Gasoline Engines
If your vehicle has a diesel engine, see
“How to Add Coolant to the Coolant Recovery
Tank” under “Van Models” in the Cooling System
section of the DURAMAX
®Diesel Supplement
for the proper coolant fill procedure.
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If you have not found a problem yet, but the
coolant level is not at the COLD FILL mark,
add a 50/50 mixture of clean, drinkable water
and DEX-COOL
®engine coolant at the coolant
recovery tank. SeeEngine Coolant on page 312
for more information.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as 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 would
not get the overheat warning. Your engine
could catch re and you or others could
be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.Notice:
When using concentrated washer uid,
follow the manufacturer’s instructions
for adding water.
Do not mix water with ready-to-use washer
uid. Water can cause the solution to
freeze and damage your washer uid tank
and other parts of the washer system.
Also, water does not clean as well
as washer uid.
Fill the washer uid tank only
three-quarters full when it is very cold.
This allows for uid expansion if freezing
occurs, which could damage the tank if
it is completely full.
Do not use engine coolant (antifreeze) in
your windshield washer. It can damage
the vehicle’s windshield washer system
and paint.
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.
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{CAUTION:
You can be burned if you spill coolant
on hot components in the engine
compartment. Coolant contains ethylene
glycol, and it will burn if the engine parts
are hot enough. Do not spill coolant on a
hot engine or components in the engine
compartment.
When the coolant in the coolant recovery tank
is at the COLD FILL mark, start your vehicle.
If the overheat warning continues, there is
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.
{CAUTION:
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
for Gasoline Engines
If your vehicle has a diesel engine, see
“How to Add Coolant to the Radiator” under
“Van Models” in the Cooling System section
of the DURAMAX
®Diesel Supplement for the
proper radiator fill procedure.
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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. Do not
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.3. Fill the radiator with the proper DEX-COOL®
coolant mixture, up to the base of the filler
neck. SeeEngine Coolant on page 312
for more information about the proper
coolant mixture.
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4. Then fill the coolant recovery tank to the
COLD FILL mark.
5. Put the cap back on the coolant recovery tank,
but leave the radiator pressure cap off.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 filler neck may be lower. If the level is
lower, add more of the proper DEX-COOL
®
coolant mixture through the filler neck until the
level reaches the base of the filler neck.
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.
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