engine CHEVROLET SILVERADO 2008 2.G Owners Manual

Coolant Surge Tank Pressure Cap
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.
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 5-14for more
information on location.
Engine Overheating
If your vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information.
You will nd a coolant temperature gage on your
vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 3-48.
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.
SeeDIC Warnings and Messages on page 3-66.
If Steam Is Coming From Your Engine
{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
your engine if it overheats, and get out of the
vehicle until the engine is cool.
SeeOverheated Engine Protection Operating
Mode (V8 Engines Only) on page 5-34for
information on driving to a safe place in an
emergency.
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Notice:If your engine catches re because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would not be
covered by your warranty. SeeOverheated Engine
Protection Operating Mode (V8 Engines Only)
on page 5-34for information on driving to a safe
place in an emergency.
If No Steam Is Coming From
Your Engine
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 4-55.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. If you have an air conditioner and it is on, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and 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 you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning does not come back on, you can drive
normally.
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If the warning continues, pull over, stop, and park your
vehicle immediately.
If there is still no sign of steam and your vehicle has an
engine-driven cooling fan, push down the accelerator
until the engine speed is about twice as fast as normal
idle speed for at least ve minutes while you are parked.
If there is still no sign of steam and your vehicle has an
electric cooling fan, idle the engine for ve minutes
while you are parked.
If you still have the warning, turn off the engine and
get everyone out of the vehicle until it cools down.
Also, see “Overheated Engine Protection Operating
Mode” later in this section.
You may decide not to lift the hood but to get service
help right away.Overheated Engine Protection
Operating Mode (V8 Engines Only)
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 your 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 (Gasoline
Engine) on page 5-15.
5-34

Cooling System
If your vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information.
When you decide it is safe to lift the hood, here is what
you will see:
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Cooling Fan
{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.
If the coolant inside the coolant surge tank is boiling,
do not do anything else until it cools down. The vehicle
should be parked on a level surface. Check the
coolant level after the system cools down. Some amount
of coolant may be lost due to overheating.
5.3L Engine (4.3L, 4.8L and 6.0L Similar)
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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 at the pressure cap
or in the radiator hoses, heater hoses, radiator, water
pump, or somewhere else in the cooling system.
{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:Engine damage from running your engine
without coolant is not covered by your warranty.
SeeOverheated Engine Protection Operating Mode
(V8 Engines Only) on page 5-34for information
on driving to a safe place in an emergency.
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 the warranty. Always use
DEX-COOL
®(silicate-free) coolant in the vehicle.
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How to Add Coolant to the Coolant
Surge Tank for Gasoline Engines
If your vehicle has a diesel engine, see “Cooling
System” in the DURAMAX®Diesel Supplement for the
proper coolant ll procedure.
If you have not found a problem yet, check to see
if coolant is visible in the surge tank. 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, including
the coolant surge tank pressure cap, is cool before
you do it. SeeEngine Coolant on page 5-29for more
information.If no coolant is visible in the surge tank, add coolant
as follows:
{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.
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{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 a proper coolant.
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.
{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.
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. Then 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. Then 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.
5-39

Engine Fan Noise
If 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 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 your 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 your
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.
5-40

Power Steering Fluid
SeeEngine Compartment
Overview on page 5-14for
reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power steering uid
unless you suspect there is a leak in the system or
you hear an unusual noise. A uid loss in this system
could indicate a problem. Have the system inspected
and repaired.
How to Check Power Steering Fluid
To check the power steering uid, do the following:
1. Turn the key off and let the engine compartment
cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a
clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the uid level
on the dipstick.
The level should be at the FULL COLD mark.
If necessary, add only enough uid to bring the
level up to the mark.
What to Use
To determine what kind of uid to use, see
Recommended Fluids and Lubricants on page 6-14.
Always use the proper uid.
Notice:Use of the incorrect uid may damage your
vehicle and the damages may not be covered by
your warranty. Always use the correct uid listed in
Recommended Fluids and Lubricants on page 6-14.
5-41