engine GMC SIERRA 2009 Owner's Manual

Consistency of Readings
Always check the uid level at least twice using the
procedure described previously. Consistency (repeatable
readings) is important to maintaining proper uid level. If
readings are still inconsistent, contact your dealer/retailer.
Cooling System
If your vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information.
The Cooling System allows the engine to maintain the
correct working temperature.
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Cooling Fan5.3L Engine (4.3L, 4.8L, 6.0L and 6.2L Similar)
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{CAUTION:
An electric engine cooling fan can start even when
the engine is not running. To avoid injury, always
keep hands, clothing, and tools away from any
engine cooling fan.
{CAUTION:
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 re, and you could be burned.
Get any leak xed 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 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by the vehicle warranty.
Always use DEX-COOL
®(silicate-free) coolant in
the vehicle.
Engine Coolant
The cooling system in the vehicle is lled with
DEX-COOL®engine coolant. This coolant is designed
to remain in the vehicle for ve years or 150,000 miles
(240 000 km), whichever occurs rst.
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, seeEngine
Overheating on page 5-34.
5-29

What to Use
{CAUTION:
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 you would not get the overheat
warning. The engine could catch re 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−34°F (−37°C),
outside temperature.
Gives boiling protection up to 265°F (129°C),
engine temperature.
Protects against rust and corrosion.
Will not damage aluminum parts.
Helps keep the proper engine temperature.
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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. SeeRecommended Fluids and
Lubricants on page 6-15for more information.Checking Coolant
The coolant surge tank is located in the engine
compartment on the passenger side of the vehicle.
SeeEngine Compartment Overview on page 5-14for
more information on location.
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 surge tank,
but be sure the cooling system is cool before this is done.
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The coolant level should be at or above the FULL
COLD mark. If it is not, you may have a leak in the
cooling system.
If the vehicle has a low coolant sensor and the LOW
COOLANT LEVEL message comes on and stays on,
it means you are low on engine coolant. See “LOW
COOLANT LEVEL” underDIC Warnings and Messages
on page 3-66.
How to Add Coolant to the Coolant
Surge Tank for Gasoline Engines
If the vehicle has a diesel engine, see “Cooling System”
in the DURAMAX®Diesel Supplement for the proper
coolant ll procedure.
{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.
Notice:This vehicle has a specic coolant ll
procedure. Failure to follow this procedure could
cause the engine to overheat and be severely
damaged.
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{CAUTION:
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.
{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 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.If no coolant is visible in the surge tank, add coolant as
follows:
1. Remove the coolant
surge tank pressure
cap when the cooling
system, including the
coolant surge tank
pressure cap and
upper radiator hose,
is no longer hot.
Turn the pressure cap slowly counterclockwise
about one full turn. 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.
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3. Fill the coolant surge tank with the proper mixture
to the FULL COLD mark.
4. With the coolant surge tank pressure cap off,
start the engine and let it run until the engine
coolant temperature gage indicates approximately
195°F (90°C).
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 reaches the FULL COLD mark.5. Replace the pressure cap. Be sure the pressure
cap is hand-tight and fully seated.
6. Verify coolant level after engine is shut off and the
coolant is cold. If necessary, repeat coolant ll
procedure Steps 1 through 6.
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
If the vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information.
The vehicle has several indicators to warn of engine
overheating.
You will nd a coolant temperature gage on the vehicle’s
instrument panel. SeeEngine Coolant Temperature
Gage on page 3-44.
In addition, you will nd ENGINE OVERHEATED STOP
ENGINE, ENGINE OVERHEATED IDLE ENGINE, and
ENGINE POWER IS REDUCED messages in the Driver
Information Center (DIC) on the instrument panel. See
DIC Warnings and Messages on page 3-66.
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You may decide not to lift the hood when this warning
appears, but instead get service help right away.
SeeRoadside Assistance Program on page 7-7.
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 fans are
running. If the engine is overheating, both fans should
be running. If they are 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.
SeeOverheated Engine Protection Operating Mode
on page 5-37for information on driving to a safe
place in an emergency.
Notice:If the engine catches re while driving with
no coolant, the vehicle can be badly damaged.
The costly repairs would not be covered by
the vehicle warranty. SeeOverheated Engine
Protection Operating Mode on page 5-37for
information on driving to a safe place in an
emergency.If Steam Is Coming From The Engine
Compartment
{CAUTION:
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 re. You or
others could be badly burned. Stop the engine if it
overheats, and get out of the vehicle until the
engine is cool.
SeeOverheated Engine Protection Operating
Mode on page 5-37for information on driving to a
safe place in an emergency.
5-35

If No Steam Is Coming From The
Engine Compartment
The ENGINE OVERHEATED STOP ENGINE or the
ENGINE OVERHEATED IDLE ENGINE message, along
with a low coolant condition, can indicate a serious
problem.
If you get an engine overheat warning, but see or hear
no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. SeeTowing a Trailer on page 4-51.If you get the ENGINE OVERHEATED STOP ENGINE or
the ENGINE OVERHEATED IDLE ENGINE message
with no sign of steam, try this for a minute or so:
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 you are stopped in a traffic jam, apply the brake,
shift to N (Neutral); otherwise, shift to the highest
gear while driving—D(Drive) or 3 (Third).
If the temperature overheat gage 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
ve minutes while parked. If the warning is still
displayed, turn off the engine until it cools down.
Also, see “Overheated Engine Protection Operating
Mode” later in this section.
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Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates ring groups
of cylinders helps prevent engine damage. In this mode,
you will notice a loss in power and engine performance.
This operating mode allows the vehicle to be driven to a
safe place in an emergency. Driving extended miles (km)
and/or towing a trailer in the overheat protection mode
should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant loss, change the oil and reset the oil
life system. SeeEngine Oil on page 5-15.
Engine Fan Noise
If the 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 everyday driving conditions,
the fan is spinning slower and 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 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 disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
If the vehicle has electric cooling fans, you may hear
the fans spinning at low speed during most everyday
driving. The fans may turn off if no cooling is required.
Under heavy vehicle loading, trailer towing, and/or
high outside temperatures, or if you are operating the
air conditioning system, the fans may change to
high speed and you may hear an increase in fan noise.
This is normal and indicates that the cooling system
is functioning properly. The fans will change to low
speed when additional cooling is no longer required.
5-37