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1. You can 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 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, but now push
down as you turn it. Remove the pressure cap.3. Fill the radiator with the proper DEX-COOL®
coolant mixture, up to the base of the filler
neck. SeeEngine Coolant on page 5-25for more
information about the proper coolant mixture.
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4. Then fill the coolant recovery tank to the
COLD FILL mark.
5. Put the cap back on the coolant recovery tank,
but leave the radiator pressure cap off.6. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fan.
7. By this time, the coolant level inside the radiator
filler neck may be lower. If the level is lower, add
more of the proper DEX-COOL
®coolant mixture
through the filler neck until the level reaches
the base of the filler neck.
8. Then replace the pressure cap. At any time during
this procedure if coolant begins to flow out of the
filler neck, reinstall the 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.
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Page 273 of 406

Radiator Pressure Cap
The radiator pressure cap is located near the center of
the engine compartment. SeeEngine Compartment
Overview on page 5-14for more information on location.
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 your vehicle has the DURAMAX Diesel engine, see
the DURAMAX Diesel manual for more information.
The vehicle has an indicator to warn of engine
overheating.
You will find an engine coolant temperature gage on
your vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 3-33for more information.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.
See if the engine cooling fan speed increases when idle
speed is doubled by pushing the accelerator pedal down.
If it does not, your vehicle needs service. Turn off the
engine.
Notice:Engine damage from running the engine
without coolant is not covered by the warranty.
Notice:If the engine catches re because of being
driven with no coolant, your vehicle can be badly
damaged. The costly repairs would not be covered
by the vehicle warranty.
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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. Just 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 your engine is overheated,
the liquids in it can catch fire. You or others could
be badly burned. Stop your engine if it overheats,
and get out of the vehicle until the engine is 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
Towing a Trailer on page 4-28.
If the overheat warning is displayed with no sign of
steam:
1. Turn the air off.
2. Turn the heater on to the highest temperature and
to the highest fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle in 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.
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Page 277 of 406

Windshield Washer Fluid
What to Use
When you need windshield washer fluid, be sure to read
the manufacturer’s instructions before use. If you will be
operating your 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. SeeEngine
Compartment Overview
on page 5-14for reservoir
location.Notice:
When using concentrated washer uid, follow
the manufacturer’s instructions for adding water.
Do not mix water with ready-to-use washer uid.
Water can cause the solution to freeze and
damage your washer uid tank and other parts of
the washer system. Also, water does not clean as
well as washer uid.
Fill the washer uid tank only three-quarters
full when it is very cold. This allows for uid
expansion if freezing occurs, which could
damage the tank if it is completely full.
Do not use engine coolant (antifreeze) in your
windshield washer. It can damage the vehicle’s
windshield washer system and paint.
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Scheduled Maintenance
Service MaintenanceIMaintenanceII
Change engine oil and filter. SeeEngine Oil on page 5-15. Reset oil life system.
SeeEngine Oil Life System on page 5-18.An Emission Control Service.••
Lubricate chassis components.See footnote #.••
Visually check for any leaks or damage.See footnote (j).••
Inspect engine air cleaner filter. If necessary, replace filter. SeeEngine Air
Cleaner/Filter on page 5-20.See footnote (l).•
Rotate tires and check inflation pressures and wear. SeeTire Inspection and
Rotation on page 5-70and “Tire Wear Inspection” inAt Least Once a Month on
page 6-11.••
Inspect brake system.See footnote (a).••
Check engine coolant and windshield washer fluid levels and add fluid as
needed.••
Perform any needed additional services. See “Additional Required Services” in
this section.••
Inspect suspension and steering components.See footnote (b).•
Inspect engine cooling system.See footnote (c).•
Inspect wiper blades.See footnote (d).•
Inspect restraint system components.See footnote (e).•
Lubricate body components.See footnote (f).•
Check transmission fluid level and add fluid as needed.•
Inspect shields, vehicles with GVWR above 10,000 lbs (4 536 kg) only.
See footnote (g).•
Inspect throttle system.See footnote (m).•
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(g)Vehicles with Gross Vehicle Weight Rating (GVWR)
above 10,000 lbs (4 536 kg) only: Inspect shields for
damage or looseness. Adjust or replace as required.
This is a Noise Emission Control Service. Applicable to
vehicles sold in the United States and recommended
for vehicles sold in Canada.
(h)Change automatic transmission fluid and filter if the
vehicle is mainly driven under one or more of these
conditions:
-In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
-In hilly or mountainous terrain.
-When doing frequent trailer towing.
-Uses such as found in taxi, police, or delivery
service.
(i)Drain, flush, and refill cooling system. This service can
be complex; you should have your dealer/retailer perform
this service. See Engine Coolant on page 5-25 for what to
use. Inspect hoses. Clean radiator, condenser, pressure
cap, and filler neck. Pressure test the cooling system and
pressure cap.
(j)A fluid loss in any vehicle system could indicate a
problem. Have the system inspected and repaired and
the fluid level checked. Add fluid if needed.(k)Inspect system. Check all fuel and vapor lines and
hoses for proper hook-up, routing, and condition. Check
that the purge valve works properly, if equipped.
Replace as needed.
(l)If driving regularly under dusty conditions, inspect the
filter at each engine oil change.
(m)Check system for interference or binding and for
damaged or missing parts. Replace parts as needed.
Replace any components that have high effort or
excessive wear. Do not lubricate accelerator or cruise
control cables.
(n)Visually inspect belt for fraying, excessive cracks, or
obvious damage. Replace belt if necessary.
(o)Check vent hose at transfer case for kinks and
proper installation. Check to be sure vent hose
is unobstructed, clear, and free of debris. During any
maintenance, if a power washer is used to clean
mud and dirt from the underbody, care should be taken
to not directly spray the transfer case output seals.
High pressure water can overcome the seals and
contaminate the transfer case fluid. Contaminated fluid
will decrease the life of the transfer case and should
be replaced.
(p)Severe Service: Change transfer case fluid if the
vehicle is mainly used for trailer towing or driven in city
traffic, wet environment, or high ambient temperatures.
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Page 364 of 406

Owner Checks and Services
These owner checks and services should be performed
at the intervals specified to help ensure vehicle safety,
dependability, and emission control performance. Your
dealer/retailer can assist with these checks and services.
Be sure any necessary repairs are completed at once.
Whenever any fluids or lubricants are added to the
vehicle, make sure they are the proper ones, as shown
inRecommended Fluids and Lubricants on page 6-14.
At the First 100, 1,000 and
6,000 Miles (160, 1 600 and
10 000 km)
For vehicles with dual wheels, check dual wheel nut
torque. For proper torque, seeCapacities and
Specifications on page 5-110.
At Each Fuel Fill
It is important to perform these underhood checks at
each fuel fill.
Engine Oil Level Check
Notice:It is important to check the engine oil
regularly and keep it at the proper level. Failure to
keep the engine oil at the proper level can cause
damage to the engine not covered by the vehicle
warranty.
Check the engine oil level and add the proper oil if
necessary. SeeEngine Oil on page 5-15.
Engine Coolant Level Check
Check the engine coolant level and add DEX-COOL®
coolant mixture if necessary. SeeEngine Coolant
on page 5-25.
Windshield Washer Fluid Level Check
Check the windshield washer fluid level in the windshield
washer fluid reservoir and add the proper fluid if
necessary.
6-10