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{WARNING:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.
{WARNING:
Heater and 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 fire, and you could be burned.
Get any leak fixed before you drive the vehicle. Notice:
Using coolant other than DEX-COOL
®can
cause premature engine, heater core, or radiator
corrosion. In addition, the engine coolant could
require changing sooner, at 50 000 km (30,000 miles)
or 24 months, whichever occurs first. Any repairs
would not be covered by the vehicle warranty.
Always use DEX-COOL
®(silicate-free) coolant
in the vehicle.
Cooling System (Intercooler)
The 6.2L LS9 supercharged V8 engine has an
intercooler cooling system. See Engine Compartment
Overview
on page 6‑14for location of the intercooler.
The intercooler cooling system has a special procedure
for draining and adding coolant. Because this procedure
is difficult, see your dealer/retailer for service if the
intercooler is low on coolant. The procedure can also
be found in the service manual. To purchase a service
manual, see Service Publications Ordering Information
on page 8‑16.
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Checking Coolant
1. Verify that the engine and intercooler are no longer hot.
2. Place a cloth to absorb possible coolant loss under the driver's side bleeder valve (A). 3. Loosen, but do not completely unscrew the bleeder
valve to check for coolant in the system.
4. Tighten the bleeder valve if there is coolant flowing out of the bleeder valve.
5. If there is no coolant flowing out of the bleeder valve, there could be a leak in the system. Tighten
the bleeder valve and contact your dealer/retailer
for service.
Engine Coolant
The cooling system in the vehicle is filled with
DEX-COOL®engine coolant. This coolant is designed
to remain in the vehicle for five years or 240 000 km
(150,000 miles), whichever occurs first.
The following explains the cooling system and how
to check and add coolant when it is low. If there is
a problem with engine overheating, see Engine
Overheating on page 6‑38.
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What to Use
{WARNING:
Adding only plain water to the cooling system
can be dangerous. Plain water, or some other
liquid such as alcohol, can boil before the proper
coolant mixture will. The vehicle's coolant warning
system is set for the proper coolant mixture.
With plain water or the wrong mixture, the engine
could get too hot but would not get the overheat
warning. The engine could catch fire and you or
others could be burned. Use a 50/50 mixture of
clean, drinkable water and DEX-COOL
®coolant.
Use a 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant. If using this mixture, nothing else
needs to be added. This mixture:
.Gives freezing protection down to −37°C (−34°F),
outside temperature.
.Gives boiling protection up to 129°C (265°F),
engine temperature.
.Protects against rust and corrosion.
.Will not damage aluminum parts.
.Helps keep the proper engine temperature. Notice:
If an improper coolant mixture is used,
the engine could overheat and be badly damaged.
The repair cost would not be covered by the vehicle
warranty. Too much water in the mixture can freeze
and crack the engine, radiator, heater core, and
other parts.
Notice: If extra inhibitors and/or additives are used
in the vehicle's cooling system, the vehicle could be
damaged. Use only the proper mixture of the engine
coolant listed in this manual for the cooling system.
See Recommended Fluids and Lubricants
on
page 7‑10for more information.
Checking Coolant
The vehicle must be on a level surface when checking
the coolant level.
Check to see if coolant is visible in the coolant surge
tank. If the coolant inside the coolant surge tank is
boiling, do not do anything else until it cools down.
If coolant is visible but the coolant level is not at or
above the FULL COLD mark, add a 50/50 mixture of
clean, drinkable water and DEX-COOL coolant at the
coolant recovery tank, but be sure the cooling system
is cool before this is done. See Engine Coolant
on
page 6‑34for more information.
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The engine coolant surge
tank is located toward
the rear of the engine
compartment on the
driver side of the vehicle.
See Engine Compartment
Overview
on page 6‑14for more information on
location.
When the engine is cold, the coolant level should be at
the FULL COLD mark on the coolant surge tank.
When the engine is hot, the level could be higher
than the FULL COLD line. If the coolant is below the
FULL COLD line when the engine is hot, there could
be a leak in the cooling system.
If the coolant is low, add the coolant or take the vehicle
to a dealer/retailer for service.
How to Add Coolant to the Coolant
Surge Tank
{WARNING:
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.
{WARNING:
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 coolant surge
tank pressure cap —even a little —they can come
out at high speed. Never turn the cap when the
cooling system, including the coolant surge tank
pressure cap, is hot. Wait for the cooling system
and coolant surge tank pressure cap to cool if you
ever have to turn the pressure cap.
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If coolant is needed, add the proper DEX-COOL®
coolant mixture directly to the surge tank, but be sure
the cooling system is cool before this is done.
1. When the cooling system, including the coolant surge tank pressure cap and upper radiator hose,
is no longer hot, remove the pressure cap.
Turn the pressure cap slowly counterclockwise
about one-quarter turn and then stop.
If you hear a hiss, wait for that to stop. A hiss
means there is still some pressure left.
2. Keep turning the pressure cap slowly, and remove it.
3. Fill the coolant surge tank with the proper DEX-COOL coolant mixture until the level inside
stabilizes at the FULL COLD mark on the front of
the surge tank.
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4. With the coolant surge tank pressure cap off, start the engine and let it run until you can feel the
upper radiator hose getting hot. Any time during
this procedure, watch out for the engine
cooling fan.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mixture to the coolant surge
tank until the level stabilizes at the FULL COLD
mark on the coolant surge tank. 5. Replace the pressure cap. Be sure the pressure
cap is hand-tight and fully seated.
Check the level in the surge tank when the system
has cooled down. If the coolant is not at the proper
level, repeat Steps 1 through 4, then reinstall the
pressure cap. If the coolant is not at the proper
level when the system cools down again, see your
dealer/retailer.
Notice: If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
Engine Overheating
The vehicle has several indicators to warn of engine
overheating.
There is an engine coolant temperature gauge on
the instrument panel cluster. See Engine Coolant
Temperature Gauge
on page 4‑40. The vehicle may
also display a COOLANT OVER TEMPERATURE
message on the Driver Information Center (DIC).
See DIC Warnings and Messages
on page 4‑52for more information.
You may decide not to lift the hood but to get service
help right away. See Roadside Assistance Program
on
page 8‑7.
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If you do decide to lift the hood , make sure the vehicle
is parked on a level surface.
Then check to see if the engine cooling fan is running.
If the engine is overheating, the fan should be running.
If it is not, do not continue to run the engine and have
the vehicle serviced.
Notice: Engine damage from running your engine
without coolant is not covered by your warranty.
See Overheated Engine Protection Operating Mode
on page 6‑41for information on driving to a safe
place in an emergency.
Notice: If the engine catches fire while driving
with no coolant, the vehicle can be badly damaged.
The costly repairs would not be covered by the
vehicle warranty. See Overheated Engine Protection
Operating Mode
on page 6‑41for information on
driving to a safe place in an emergency.
If Steam Is Coming From Your Engine
{WARNING:
Steam from an overheated engine can burn you
badly, even if you just open the hood. Stay away
from the engine if you see or hear steam coming
from it. Turn it off and get everyone away from
the vehicle until it cools down. Wait until there
is no sign of steam or coolant before you open
the hood.
If you keep driving when the vehicles engine is
overheated, the liquids in it can catch fire. You or
others could be badly burned. Stop the engine if
it overheats, and get out of the vehicle until the
engine is cool.
See Overheated Engine Protection Operating
Mode
on page 6‑41for information on driving to
a safe place in an emergency.
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If No Steam Is Coming From Your
Engine
If an engine overheat warning is displayed but no steam
can be seen or heard, the problem may not be too
serious. Sometimes the engine can get a little too hot
when the vehicle:
.Climbs a long hill on a hot day.
.Stops after high-speed driving.
.Idles for long periods in traffic.
If the overheat warning is displayed with no sign of
steam: 1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest fan speed. Open the windows as
necessary.
3. If in a traffic jam, shift to N (Neutral) while stopped. If it is safe to do so, pull off the road, shift to
P (Park) or N (Neutral) and let the engine idle. If the temperature overheat gauge is no longer in
the overheat zone or an overheat warning no longer
displays, the vehicle can be driven. Continue to drive
the vehicle slow for about 10 minutes. Keep a safe
vehicle distance from the car in front of you. If the
warning does not come back on, continue to drive
normally.
If the warning continues, pull over, stop, and park the
vehicle right away.
If there is no sign of steam, idle the engine for
three minutes while parked. If the warning is still
displayed, turn off the engine until it cools down.
Also, see
“Overheated Engine Protection Operating
Mode” next in this section.
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