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What to Use
Use a mixture of one-half clean, drinkable water and
one-half DEX-COOL®coolant which will not damage
aluminum parts. If you use this coolant mixture, you do
not need to add anything else.
{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 the proper coolant.Notice:If you use an improper coolant mixture,
your engine could overheat and be badly damaged.
The repair cost would not 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 extra inhibitors and/or additives
in your vehicle’s cooling system, you could
damage your vehicle. Use only the proper mixture
of the engine coolant listed in this manual for
the cooling system. SeeRecommended Fluids and
Lubricants (Gasoline Engine) on page 6-13for
more information.
5-22
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Checking Coolant for Gasoline Engines
If your vehicle has a diesel engine, see “Checking
Coolant” under “Van Models” in the DURAMAX®Diesel
Supplement for information on checking your vehicle’s
coolant.
The coolant recovery tank
is located near the center
of the engine
compartment. SeeEngine
Compartment Overview
on page 5-12for more
information on location.
The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the COLD
FILL mark, or a little higher.
Adding Coolant
If you need more coolant, add the proper DEX-COOL®
coolant mixture at the coolant recovery tank, but be
careful not to spill it.
{CAUTION:
Turning the radiator pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. With the coolant recovery tank, you will
almost never have to add coolant at the
radiator. Never turn the radiator pressure
cap — even a little — when the engine and
radiator are hot.
{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. Do not spill coolant on a hot engine.
Occasionally check the coolant level in the radiator. For
information on how to add coolant to the radiator,
seeCooling System on page 5-26.
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Cooling System
If your vehicle has a diesel engine, see “Van Models”
under “Cooling System” in the DURAMAX®Diesel
Supplement.
When you decide it is safe to lift the hood, here is what
you will see:
A. Radiator Pressure Cap
B. Coolant Recovery Tank
C. Engine Cooling Fan(s)If the coolant inside the coolant recovery tank is boiling,
do not do anything else until it cools down.
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.
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{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 may
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.
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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.
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 5-21for 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.
5-28
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