2003 GMC YUKON DENALI engine coolant

If No Steam Is Coming From Your
Engine
An overheat warning, along with a low coolant message,
can indicate a serious problem. See
Low Coolant
Level Warning Message under DIC Warnings and
Messages
on page 3-52.
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:
0 Climb a long hill on a hot day.
Stop after high-speed driving.
0 Idle for long periods in traffic.
0 Tow a trailer. See Towing a Trailer on page 4-47.
If you get the overheat warning with no sign of steam, try
this for a minute or so:
1. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
If you no longer have the overheat warning, you can
drive. Just
to be safe, drive slower for about 10 minutes.
If the warning doesn’t come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there’s 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
you’re 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” listed previously in this section.
You may decide not
to lift the hood but to get service
help right away.
2. If you’re in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
- DRIVE (D).
5-27

Cooling System
When you decide it’s safe to lift the hood, here’s what
you’ll see: If the
coolant inside the coolant surge tank
is boiling,
don’t do anything else until
it cools down. The vehicle
should be parked on a level surface.
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Fan
1
The coolant level should
be at or above the FULL
COLD mark. If
it isn’t,
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.
5-28

Heater and rac.-:or hoses, and other engine
parts, can be very hot. Don’t touch them. If you
do, you can be burned.
Don’t run the engine
if there is a leak. If you
run
the engine, it could lose all coolant. That
could cause an engine fire, and you could be
burned. Get any leak fixed before you drive the
vehicle.
If there seems to be no leak, start the engine again.
The engine cooling fan speed should increase when idle
speed is doubled by pushing the accelerator pedal
down. If it doesn’t, your vehicle needs service. Turn
off
the engine.
Notice: Engine damage from running your engine
without coolant isn’t covered by your warranty.
See “Overheated Engine Protection Operating
Mode”
in the Index for information on driving to a
safe place
in an emergency.
Notice: When adding coolant, it is important that
you use only
DEX-COOL@ (silicate-free) coolant.
If coolant other than DEX-COOL@ is added to
the system, premature engine, heater core or radiator corrosion
may result. In addition, the engine
coolant will require change sooner
- at 30,000 miles
(50 000 km) or 24 months, whichever occurs first.
Damage caused by
the use of coolant other
than DEX-COOL@ is not covered by your new vehicle
warranty.
How to Add Coolant to the Coolant
Surge Tank
If you haven’t found a problem yet, check to see if
coolant is visible in the surge tank. If coolant is visible
but the coolant level isn’t 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. See Engine Coolant on
page 5-22 for more
information.
If no coolant is visible in the surge tank, add coolant as
follows:
5-29

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 wouldn't get the overheat warning.
Your engine could catch fire and you or others
could be burned. Use a
50/50 mixture of clean,
drinkable water and DEX
COOL@ 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. You can be burned
if you spill coolant on tist
engine parts. Coolant contains ethylene glycol
and
it will burn if the engine parts are hot
enough. Don't
spill coolant on a hot engine.
1. Park the vehicle on a
level surface.
SURGE RESERVOIR
15 PSI
TANK - 105 kPa
D'EXPANSION I
You
can 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
(left) about one full turn. If you hear a hiss, wait for
that
to stop. A hiss means there is still some
pressure left.
5-31

4. With the coolant surge tank pressure cap off, start
the engine and let it run until you can feel the upper
radiator hose getting hot. Watch out for the
engine cooling fan.
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
FULL COLD mark.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch
is engaged, the fan spins faster to provide
more air
tu 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.
5-33

Adding Washer Fluid
Your vehicle has a low washer fluid message that
comes on when the washer fluid
is low. The message is
displayed for
15 seconds at the star? of each ignition
cycle. When the LOW
WASHER FLUID message
is displayed, you will need to add washer fluid to the
windshield washer fluid reservoir.
The windshield washer
the engine compartment
toward the front of the
vehicle on the driver’s side.
4-4- fluid reservoir is located in 111
W
Open the cap with the washer symbol on it. Add washer
fluid until the tank is full.
Notice:
When using concentrated washer fluid, follow
the manufacturer’s instructions for adding water.
Don’t mix water with ready-to-use washer fluid.
Water can cause the solution to freeze and
damage your washer
fluid tank and other parts
of the washer system.
Also, water doesn’t
clean as well as washer fluid.
Fill your washer fluid tank only three-quarters
full when it’s very cold. This allows for expansion if freezing occurs, which could damage the tank if
it is completely full.
Don’t use engine coolant (antifreeze)
in your
windshield washer.
It can damage your
washer system and paint.
5-35

Part B: Owner Checks and Services
Listed in this part are owner checks and services
which should be performed at the intervals specified
to
help ensure the safety, dependability and emission
control performance of your vehicle.
Be sure any necessary repairs are completed at once.
Whenever any fluids or lubricants are added
to your
vehicle, make sure they are the proper ones, as shown
in Part
D.
At Each Fuel Fill
It is important for you or a service station attendant to
perform these underhood checks at each fuel fill.
Engine Oil Level Check
Check the engine oil level and add the proper oil if
necessary. See Engine Oil on page 5-13 for further
details.
Engine Coolant Level Check
Check the engine coolant level and add DEX-COOL@
coolant mixture
if necessary. See Engine Coolant
on page 5-22 for further details.
Windshield Washer Fluid Level Check
Check the windshield washer fluid level in the windshield
washer tank and add the proper fluid
if necessary.
See Windshield Washer Fluid
on page 5-34 for further
details.
At Least Once a Month
Tire Inflation Check
Make sure tries are inflated to the correct pressures.
Don’t forget
to check your spare tire. See Tires on
page 5-55 for further details.
Cassette Tape Player Service
Clean cassette tape player. Cleaning should be done
every
50 hours of tape play. See Audio System(s)
on page 3-58 for further details.
At Least Twice a Year
Restraint System Check
Make sure the safety belt reminder light and all your
belts, buckles, latch plates, retractors and anchorages
are working properly. Look for any other loose or
damaged safety belt system parts. If you see anything
that might keep a safety belt system from doing its
job, have it repaired. Have any torn or frayed safety belts
replaced.
6-1 0

Part D: Recommended Fluids and
Lubricants
Flyids and lubricants identified below by mme,
part number or specification may be obtained from
your dealer.
Usage
Engine Oil
Engine Coolant
Hydraulic Brake
System
Windshield
Washer Solvent
Fluid/Lubricant
Engine oil with the American
Petroleum Institute Certified for
Gasoline Engines starburst symbol
of the proper viscosity. To determine
the preferred viscosity for your
vehicle's engine, see Engine
Oil on
page
5- 13.
50/50 mixture of clean, drinkable
water and use only
DEX-COOL@Coolant. See Engine
Coolant on page
5-22.
Delco Supreme 1 l@ Brake Fluid or
equivalent
DOT-3 brake fluid.
GM Optikleen@Washer Solvent or
equivalent.
Usage
Power Steering System
Automatic
Transmission
Key Lock
Cylinders
Chassis
Lubrication
Front and
Rear Axle
Transfer Case
Fluid/Lubricant
GM Power Steering Fluid (GM Part No.
U.S. 1052884, in Canada
993294, or equivalent).
DEXRON@-Ill Automatic
Transmission Fluid.
Mulit-Purpose Lubricant, Superlube
(GM Part No.
U.S. 12346241 , in
Canada 10953474, or equivalent).
Chassis Lubricant (GM Part No.
U.S. 12377985, in Canada
88901242, or equivalent) or lubricant
meeting requirements of NLGl
#2,
Category LB or GC-LB.
SAE 75W-90 Synthetic Axle Lubricant (GM Part
No. U.S.
12378261, in Canada 10953455) or
equivalent meeting GM Specification
99861
15.
DEXRON@-Ill Automatic
Transmission Fluid.
6-1 5