.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 7‑12for more information.
Checking Coolant
The coolant surge tank is located in the engine
compartment on the passenger side of the vehicle. See
Engine Compartment Overview
on page 6‑16for 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.
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 4‑65.
6-32
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 fill procedure.
{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.
Notice: This vehicle has a specific coolant fill
procedure. Failure to follow this procedure could
cause the engine to overheat and be severely
damaged.
{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:
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.
6-33
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.
3. Fill the coolant surge tank with the proper mixtureto 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 fill
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 find a coolant temperature gage on the
vehicle's instrument panel. See Engine Coolant
Temperature Gage on page 4‑41.
In addition, you will find 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 4‑65.
6-34
You may decide not to lift the hood when this warning
appears, but instead get service help right away.
SeeRoadside Assistance Program on page 8‑7.
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.
See Overheated Engine Protection Operating Mode
on page 6‑36for 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 6‑36for information on
driving to a safe place in an emergency.
If Steam Is Coming From The Engine
Compartment
{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 6‑36for information on driving to
a safe place in an emergency.
6-35
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 5‑50.
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
five 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.
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 firing 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.
6-36
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. See Engine Oil
on
page 6‑18.
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.
Power Steering Fluid
See
Engine Compartment
Overviewon page 6‑16for reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power steering
fluid unless you suspect there is a leak in the system or
you hear an unusual noise. A fluid loss in this system
could indicate a problem. Have the system inspected
and repaired.
6-37
Notice:
.When using concentrated washer fluid,
follow the manufacturer's instructions for
adding water.
.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. Also, water does
not clean as well as washer fluid.
.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.
.Do not use engine coolant (antifreeze) in the
windshield washer. It can damage the
vehicle's windshield washer system and
paint.
Brakes
Brake Fluid
The brake master cylinder
reservoir is filled with DOT
3 brake fluid. SeeEngine
Compartment Overview
on page 6‑16for the
location of the reservoir.
There are only two reasons why the brake fluid level in
the reservoir might go down:
.The brake fluid level goes down because of
normal brake lining wear. When new linings are
installed, the fluid level goes back up.
.A fluid leak in the brake hydraulic system can also
cause a low fluid level. Have the brake hydraulic
system fixed, since a leak means that sooner or
later the brakes will not work well.
6-39
When the Change Engine Oil Soon message
displays, certain services, checks, and inspections are
required. The services described for MaintenanceI
should be performed at every engine oil change.
The services described for Maintenance IIshould be
performed when:
.Maintenance Iwas performed the last time the
engine oil was changed.
.It has been 10 months or more since the Change
Engine Oil Soon message has displayed or since
the last service.
Maintenance I
.Change engine oil and filter. See Engine Oilon
page 6‑18. An Emission Control Service.
.Engine coolant level check. See Engine Coolanton page 6‑31.
.Windshield washer fluid level check. See
Windshield Washer Fluid on page 6‑38.
.Tire inflation check. SeeInflation - Tire Pressureon page 6‑72.
.Tire wear inspection. See Tire Inspection and
Rotation on page 6‑80.
.Rotate tires. See Tire Inspection and Rotationon
page 6‑80.
.Fluids visual leak check (or every 12 months,
whichever occurs first). A leak in any system
must be repaired and the fluid level checked.
.Engine air cleaner filter inspection (vehicles
driven in dusty conditions only). See Engine Air
Cleaner/Filter on page 6‑21.
.Brake system inspection (or every 12 months,
whichever occurs first).
.For vehicles with Allison Transmission®only:
At the first engine oil change only, replace external
transmission filter.
Maintenance II
.Perform all services described in Maintenance I.
.Steering and suspension inspection. Visual
inspection for damaged, loose, or missing parts or
signs of wear.
.Lubricate the front suspension, steering linkage,
and parking brake cable guides. Control arm
ball joints on 2500/3500 series vehicles require
lubrication but should not be lubricated unless their
temperature is−12°C (10°F) or higher, or they
could be damaged. Control arm ball joints on
1500 series vehicles are maintenance‐free.
Vehicles used under severe commercial operating
conditions require lubrication on a regular basis
every 5 000 km/3,000 miles.
7-4