2003 GMC SIERRA DENALI coolant

Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade.
If you don’t shift
down, you might have to use your brakes
so much that
they would get hot and no longer work well.
You can tow in DRIVE
(5). You may want to shift the
transmission to THIRD
(3) or, if necessary, a lower gear
selection
if the transmission shifts too often (e.g.,
under heavy loads and/or hilly conditions).
You may also want to activate the tow/haul mode
if the
transmission shifts too often. See “Tow/Haul Mode”
earlier in this section.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes.
If you turn your
engine
off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar
to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine
off. If you do get
the overheat warning, see
Engine Overheating on
page
5-27.
Parking on Hills
m
You really should not park your vehicle, with a
trailer attached, on a hill.
If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But
if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK
(P) yet.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P).
5. Release the regular brakes.
4-58

Section 5 Service and Appearance Care
Service ............................................................ 5.3
Doing Your Own Service Work
......................... 5-4
Adding Equipment to the Outside
of Your Vehicle
........................................... 5-4
Fuel
................................................................ 5.5
Gasoline Octane
............................................ 5.5
Gasoline Specifications
.................................... 5.5
California Fuel
............................................... 5.6
Additives
....................................................... 5.6
Fuels in Foreign Countries
................. ....... 5.7
Filling Your Tank
......................................... 5-7
Filling a Portable Fuel Container
.................... 5-9
the Hood
............................................. 5.10
Hood Release
........................................ ,.5-10
Engine Compartment Overview
....................... 5.12
Checking
Things Under
Engine Oil
................................................... 5.13
Engine Air Cleaner/Filter
................................ 5.19
Engine Coolant
............................................. 5.24
Engine Overheating
....................................... 5.27
Cooling System
............................................ 5.30
Automatic
Transmission Fluid
........................ -5-21
Coolant Surge Tank Pressure Cap
.................. 5-27 Engine
Fan Noise
......................................... 5.36
Power Steering Fluid
..................................... 5.37
Windshield Washer Fluid
................................ 5-38
Brakes
........................................................ 5.39
Battery
........................................................ 5.42
Jump Starting
............................................... 5.43
All-Wheel Drive
......................... .............. 5-49
Rear Axle
....................................................... 5-50
Front Axle
...................................................... 5-51
Bulb Replacement
.......................................... 5-52
Halogen Bulbs
.............................................. 5-52
Headlamps
................................................. -5-52
Roof Marker Lamps
...................................... 5-54
Cargo Lamp
............................................. 5-56
Taillamps
..................................................... 5-58
Replacement Bulbs
....................................... 5-59
Front
Turn Signal, Sidemarker
and Daytime
Running Lamps
......................................... 5-53
Center High-Mounted Stoplamp (CHMSL) and
Pickup
Box Identification and Fender Marker
Lamps
..................................................... 5-58
Windshield Wiper Blade Replacement
.............. 5-60
5-
1

Checking Things Under
1-eH
od
Things ti.-- burn c2.. get on hot engine parts
and start a fire. These include liquids like fuel,
oil, coolant, brake fluid, windshield washer and
other fluids, and plastic or rubber. You or
others could be burned. Be careful not to drop or spill things that will burn onto a hot engine.
Hood Release
To open the hood do the following:
1. Pull the handle inside
the vehicle located
under and to the left
of
the steering wheel.
5-1 0

A. Engine Air CleanedFilter
B. Coolant Surge Tank
C. Air CleanerlFilter Restriction Indicator
B. Engine Oil Dipstick
E. Engine Oil Fill Cap
F. Automatic Transmission Dipstick
G. Fan
H. Remote Negative
(-) Terminal (GND)
I. Remote Positive (+) Terminal
J. Power Steering Fluid Reservoir
K. Brake Fluid Reservoir
L. Underhood Fuse Block
M. Battery
N. Windshield Washer Fluid Reservoir
Engine Oil
If the CHECK ENG OIL LEVEL message appears on
the instrument cluster, it means you need to check your
engine
oil level right away.
For more information, see “CHECK ENG
OIL LEVEL”
under
DIC Warnings and Messages on page 3-53.
You should check your engine oil level regularly; this is
an added reminder.
5-1 3

Engine Coolant
The cooling system in your vehicle is filled with
DEX-COOL@ engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240
000 km), whichever occurs first, if you add only
DEX-COOL@ extended life coolant.
The following explains your cooling system and how to
add coolant when
it is low. If you have a problem
with engine overheating, see
Engine Overheating on
page
5-27.
A 50/50 mixture of clean, drinkable water and
DEX-COOL@ coolant will:
Give freezing protection down to -34°F ( -37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
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.
Let the warning lights and gages work as they
should.
5-24

What to Use
Use a mixture of one-half dean, drinkable water and
one-half
DEX-COOL@ coolant which won’t damage
aluminum parts.
If you use this coolant mixture,
vou don’t need
to add anvthing else.
I
Addir - mi- -)lain water to lr cooling s- tem
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: If you use an improper coolant mixture,
your engine could overheat and be badly damaged.
The repair cost wouldn’t be covered by your
warranty. Too much water
in the mixture can freeze
and crack the engine, radiator, heater core
and
other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
Notice: If you use the proper coolant, you don’t
have to add extra inhibitors or additives which claim
to improve the system. These can be harmful.
5-25

Checking Coolant
The coolant surge tank is
located in the engine
compartment on the
passenger’s side
of the
vehicle. See
Engine
Compartment Overview
on page
5-12 for more ’
Turning the surge tank pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. Never turn the surge tank pressure
cap
- even a little - when the engine and
radiator are hot. The
vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the
FULL COLD mark.
If the LOW COOLANT LEVEL message comes on and
stays on, it means you’re low on engine coolant.
See “Low Coolant Level” under
DIC Warnings and
Messages
on page 3-53.
Adding Coolant
If you need more coolant, add the proper DEX-COOL@
coolant mixture
at the surge tank, but only when the
engine is cool.
I
You can I: burned if you spill coolant on hot
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.
I I
When replacing the pressure cap, make sure it is
hand-tight.
5-26

Coolant Surge Tank Pressure Cap
The coolant surge tank
pressure cap must be fully
installed on the coolant
surge tank.
Nofice: Your pressure cap is a pressure-type cap
and must be tightly installed to prevent coolant loss
and possible engine damage from overheating. See “Capacities and Specifications” for more
information.
Engine Overheating
You will find a coolant temperature gage on your
vehicle’s instrument panel. See
Engine Coolant
Temperature Gage
on page 3-36. In addition, you will
find a LOW COOLANT, ENGINE OVERHEATED and a
REDUCED ENGINE POWER message in the DIC on
the instrument panel. See
Driver lnformation Center
(DIC)
on page 3-43.
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 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.
Nofice: 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” in the Index.
5-27