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6.6L V8 Engine
1. Radiator Pressure Cap
2. Coolant Recovery Tank
3. Engine Cooling Fan (Out of View)
{Warning
An underhood electric fan 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
Do not touch heater or radiator hoses,
or other engine parts. They can be very
hot and can burn you. Do not run the
engine if there is a leak; all coolant could
leak out. That could cause an engine fire
and can burn you. Fix any leak before
driving the vehicle.
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
5 years or 240 000 km (150,000 mi),
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, seeEngine Overheating 0187.
What to Use
{Warning
Plain water, or other liquids such as
alcohol, can boil before the proper
coolant mixture will. With plain water or
(Continued)
Warning (Continued)
the wrong mixture, the engine could get
too hot but there would not be an
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. 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.
Caution
Do not use anything other than a mix of
DEX-COOL coolant that meets GM
Standard GMW3420 and clean, drinkable
water. Anything else can cause damage
to the engine cooling system and the
vehicle, which would not be covered by
the vehicle warranty.
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Never dispose of engine coolant by putting
it in the trash, pouring it on the ground,
or into sewers, streams, or bodies of water.
Have the coolant changed by an authorized
service center, familiar with legal
requirements regarding used coolant
disposal. This will help protect the
environment and your health.
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 recovery tank. If the coolant inside
the coolant recovery 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 indicated 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.
The coolant recovery tank cap has this
symbol on it.
When the engine is cold, the coolant level
should be at or above the COLD FILL mark.
If it is not, there could be a leak in the
cooling system.
If the coolant is low, add the coolant or take
the vehicle to a dealer for service.
How to Add Coolant to the Recovery
Tank for Gasoline Engines
{Warning
Spilling coolant on hot engine parts can
burn you. Coolant contains ethylene
glycol and it will burn if the engine parts
are hot enough.
{Warning
Plain water, or other liquids such as
alcohol, can boil before the proper
coolant mixture will. With plain water or
the wrong mixture, the engine could get
too hot but there would not be an
overheat warning. The engine could catch
fire and you or others could be burned.
{Warning
Steam and scalding liquids from a hot
cooling system are under pressure.
Turning the pressure cap, even a little,
can cause them to come out at high
speed and you could be burned. Never
turn the cap when the cooling system,(Continued)
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Warning (Continued)
including the pressure cap, is hot. Wait
for the cooling system and pressure cap
to cool.
Caution
Failure to follow the specific coolant fill
procedure could cause the engine to
overheat and could cause system
damage. If coolant is not visible in the
surge tank, contact your dealer.
If coolant is needed, add the proper
DEX-COOL coolant mixture at the coolant
recovery tank.
How to Add Coolant to the Radiator
{Warning
Steam and scalding liquids from a hot
cooling system are under pressure.
Turning the pressure cap, even a little,
can cause them to come out at high
speed and you could be burned. Never
turn the cap when the cooling system, (Continued)
Warning (Continued)
including the pressure cap, is hot. Wait
for the cooling system and pressure cap
to cool.
If coolant is needed, add the proper mixture
directly to the radiator, but be sure the
cooling system is cool before this is done.
1. 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 a hiss is heard, wait for that to stop.
A hiss means there is still some
pressure left.
2. Keep turning the pressure cap, but now push down as you turn it. Remove the
pressure cap. 3. Fill the radiator with the proper mixture,
up to the base of the filler neck. See
Recommended Fluids and Lubricants
0251 for more information about the
proper coolant mixture.
4. Remove the coolant recovery tank cap
and fill to the COLD FILL mark.
5. Reinstall the cap back on the coolant recovery tank, but leave the radiator
pressure cap off.
6. Start the engine and let it run until the upper radiator hose can be felt getting
hot. Watch out for the engine
cooling fan.
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7. By this time, the coolant level inside theradiator filler neck may be lower. If the
level is lower, add more of the proper
mixture through the filler neck until the
level reaches the base of the filler neck.
8. Replace the pressure cap. At any time during this procedure if coolant begins to
flow out of the filler neck, reinstall the
pressure cap.
Caution
If the pressure cap is not tightly installed,
coolant loss and engine damage may
occur. Be sure the cap is properly and
tightly secured.
Engine Overheating
If the vehicle has a diesel engine, see the
Duramax diesel supplement.
Caution
Do not run the engine if there is a leak
in the engine cooling system. This can
cause a loss of all coolant and can
damage the system and vehicle. Have
any leaks fixed right away. The vehicle has an indicator to warn of
engine overheating.
There is an engine coolant temperature
gauge on the vehicle's instrument cluster.
See
Engine Coolant Temperature Gauge
0 74.
If the decision is made not to lift the hood
when this warning appears, but instead get
service help right away, see Roadside
Assistance Program 0262.
If the decision is made 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, the
fan should be running. If it is not, do not
continue to run the engine and have the
vehicle serviced.
See if the engine cooling fan speed increases
when idle speed is doubled by pushing the
accelerator pedal down. If it does not, the
vehicle needs service. Turn off the engine.
If Steam is Coming from the Engine
Compartment
{Warning
Steam and scalding liquids from a hot
cooling system are under pressure.
Turning the pressure cap, even a little,
can cause them to come out at high
speed and you could be burned. Never
turn the cap when the cooling system,
including the pressure cap, is hot. Wait
for the cooling system and pressure cap
to cool.
If No Steam is Coming from the Engine
Compartment
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.
.Tows a trailer. See “Driving on Grades”
under Trailer Towing 0159.
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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. When it is safe to do so, pull off the road, shift to P (Park) or N (Neutral) and
let the engine idle.
If the engine coolant temperature 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 slowly for about 10 minutes. Keep a
safe vehicle distance from the vehicle in
front. If the warning does not come back on,
continue to drive normally and have the
cooling system checked for proper fill and
function.
If the warning continues, pull over, stop, and
park the vehicle right away.
If there is still no sign of steam, push down
the accelerator until the engine speed is
about twice as fast as normal idle speed for
at least three minutes while parked. If the
warning is still on, turn off the engine until
it cools down. If the decision is made not to lift the hood,
get service help right away.
Engine Fan
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 an increase in fan noise may be heard.
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 partially disengages.
This fan noise may be heard when starting
the engine. It will go away as the fan clutch
partially disengages.
Power Steering Fluid
The power steering fluid reservoir is in the
engine compartment on the driver side of
the vehicle. See
Engine Compartment
Overview 0176 for reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power
steering fluid unless there is a leak
suspected in the system or an unusual noise
is heard. A fluid 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 fluid:
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.
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4. Replace the cap and completelytighten it.
5. Remove the cap again and look at the fluid level on the dipstick.
The level should be at the COLD FILL mark.
If necessary, add only enough fluid to bring
the level up to the mark.
To prevent contamination of brake fluid,
never check or fill the power steering
reservoir with the brake master cylinder
cover off.
What to Use
Caution
Use of the incorrect fluid may damage
the vehicle and the damages may not be
covered by the vehicle warranty. Always
use the correct fluid listed in
Recommended Fluids and Lubricants
0251.
To determine what kind of fluid to use, see
Recommended Fluids and Lubricants 0251.
Always use the proper fluid. Failure to use
the proper fluid can cause leaks and damage
hoses and seals.
Washer Fluid
What to Use
When the vehicle needs windshield washer
fluid, be sure to read the manufacturer's
instructions before use. If operating the
vehicle in an area where the temperature
may fall below freezing, use a fluid that has
sufficient protection against freezing.
Adding Washer Fluid
Open the cap with the washer symbol on it.
Add washer fluid until the tank is full. See
Engine Compartment Overview 0176 for
reservoir location.
Caution
.Do not use washer fluid that contains
any type of water repellent coating.
This can cause the wiper blades to
chatter or skip.
(Continued)
Caution (Continued)
.Do not use engine coolant (antifreeze)
in the windshield washer. It can
damage the windshield washer system
and paint.
.Do not mix water with ready-to-use
washer fluid. Water can cause the
solution to freeze and damage the
washer fluid tank and other parts of
the washer system.
.When using concentrated washer fluid,
follow the manufacturer instructions
for adding water.
.Fill the washer fluid tank only
three-quarters full when it is very cold.
This allows for fluid expansion if
freezing occurs, which could damage
the tank if it is completely full.
Brakes
Disc brake linings have built-in wear
indicators that make a high-pitched warning
sound when the brake linings are worn and
new linings are needed. The sound can come
and go or can be heard all the time when
the vehicle is moving, except when applying
the brake pedal firmly.
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{Warning
The brake wear warning sound means
that soon the brakes will not work well.
That could lead to a crash. When the
brake wear warning sound is heard, have
the vehicle serviced.
Caution
Continuing to drive with worn-out brake
linings could result in costly brake
repairs.
Some driving conditions or climates can
cause a brake squeal when the brakes are
first applied, clearing up following several
applications. This does not mean something
is wrong with the brakes.
Properly torqued wheel nuts are necessary
to help prevent brake pulsation. When tires
are rotated, inspect brake linings for wear
and evenly tighten wheel nuts in the proper
sequence to torque specifications. See
Capacities and Specifications 0255.
Brake pads should be replaced as complete
axle sets.
Brake Pedal Travel
See your dealer if the brake pedal does not
return to normal height, or if there is a
rapid increase in pedal travel. This could be
a sign that brake service may be required.
Replacing Brake System Parts
Always replace brake system parts with
new, approved replacement parts. If this is
not done, the brakes may not work
properly. The braking performance can
change in many ways if the wrong brake
parts are installed or if parts are improperly
installed.
Brake Fluid
The brake master cylinder reservoir is filled
with GM approved DOT 4 brake fluid as
indicated on the reservoir cap. See Engine
Compartment Overview 0176 for the
location of the reservoir. Checking Brake Fluid
With the vehicle in P (Park) on a level
surface, the brake fluid level should be
between the minimum and maximum marks
on the brake fluid reservoir.
There are only two reasons why the brake
fluid level in the reservoir may go down:
.Normal brake lining wear. When new
linings are installed, the fluid level goes
back up.
.A fluid leak in the brake hydraulic system.
Have the brake hydraulic system fixed.
With a leak, the brakes will not
work well.
Always clean the brake fluid reservoir cap
and the area around the cap before
removing it.
Do not top off the brake fluid. Adding fluid
does not correct a leak. If fluid is added
when the linings are worn, there will be too
much fluid when new brake linings are
installed. Add or remove fluid, as necessary,
only when work is done on the brake
hydraulic system.
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{Warning
If too much brake fluid is added, it can
spill on the engine and burn, if the
engine is hot enough. You or others could
be burned, and the vehicle could be
damaged. Add brake fluid only when
work is done on the brake hydraulic
system.
When the brake fluid falls to a low level,
the brake warning light comes on. See Brake
System Warning Light 078.
Brake fluid absorbs water over time which
degrades the effectiveness of the brake fluid.
Replace brake fluid at the specified intervals
to prevent increased stopping distance. See
Maintenance Schedule 0245.
What to Add
Use only GM approved DOT 4 brake fluid
from a clean, sealed container. See
Recommended Fluids and Lubricants 0251.
{Warning
The wrong or contaminated brake fluid
could result in damage to the brake
system. This could result in the loss of
(Continued)
Warning (Continued)
braking leading to a possible injury.
Always use the proper GM approved
brake fluid.
Caution
If brake fluid is spilled on the vehicle's
painted surfaces, the paint finish can be
damaged. Immediately wash off any
painted surface.
Battery - North America
The original equipment battery is
maintenance free. Do not remove the cap
and do not add fluid.
Refer to the replacement number shown on
the original battery label when a new
battery is needed. SeeEngine Compartment
Overview 0176 for battery location.
{Warning
WARNING: Battery posts, terminals and
related accessories can expose you to
chemicals including lead and lead
compounds, which are known to the
(Continued)
Warning (Continued)
State of California to cause cancer and
birth defects or other reproductive harm.
Wash hands after handling. For more
information go to
www.P65Warnings.ca.gov.
See the warning on the back cover.
Vehicle Storage
{Warning
Batteries have acid that can burn you and
gas that can explode. You can be badly
hurt if you are not careful. Always wear
eye protection. See Jump Starting - North
America 0230 for tips on working
around a battery without getting hurt.
Infrequent Usage: Remove the black,
negative (−) cable from the battery to keep
the battery from running down.
Extended Storage: Remove the black,
negative (−) cable from the battery or use a
battery trickle charger.