service GMC SIERRA DENALI 2003 Repair Manual

I
Heater and radiator 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.
5-31

I 10. Connect the other
end of the
negative
(-) cable
to the negative
(-)
terminal of the dead
battery or to a remote
negative
(-) terminal
if the vehicle has one.
11. Now start the vehicle with the good battery and run
the engine for a while.
12. Try to start the vehicle that had the dead battery.
If it won’t start after a few tries, it probably needs
service.
Notice: Damage to your vehicle may result from
electrical shorting if jumper cables are removed
incorrectly.
To prevent electrical shorting, take care
that the cables don’t touch each other or any
other metal. The repairs wouldn’t be covered by
your warranty.
5-47

Rear Axle
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See
PaHA: Scheduled
Maintenance Services on page
6-4.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface. The
proper level is from
5/8 inch to 1 5/8 inch (1 5 mm to
40 mm) below the bottom of the filler plug hole. Add
only enough fluid to reach the proper level. The proper
level for vehicles with QUADRASTEERTM
(4 Wheel
Steer) is from
0 to 1/4 inch (0 to 6 mm) below the filler
plug hole. Add only enough fluid to reach the proper
level.
What to Use
Refer to the Maintenance Schedule to determine what
kind
of lubricant to use. See Part D: Recommended
Fluids and Lubricants on page
6- 16.
5-50

Front Axle
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See
Pat? A: Scheduled
Maintenance Services on page
6-4.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
If the level is below the bottom
of the filler plug hole,
you may need to add some lubricant.
When the differential is cold, add enough lubricant to
raise the level to
0 to 3/8 inch (9.5 mm) below the filler
plug hole.
When the differential is at operating temperature
(warm), add enough lubricant to raise the level to the
bottom
of the filler plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See
Pat? D: Recommended
Fluids and Lubricants on page
6-16.
5-51

I Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your
tire warranty and where to obtain service,
see your
GMC Warranty booklet for det+
Poorly maintained and improperly used tires
are dangerous.
0 Overloading your tires can cause
overheating as a result of too much
friction. You could have an air-out and a
serious accident. See "Loading Your
Vehicle" in the Index.
CAUTION: (Continued)
0 Underinflated tires pose the same danger
as overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.
0 Overinflated tires are more likely to be cut,
punctured or broken by a sudden impact
- such as when you hit a pothole.
Keep tires at the recommended pressure.
Worn, old tires can cause accidents. If
your tread
is badly worn, or if your tires
have been damaged, replace them.
5-6 1

The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The first rotation
is the most important. See “Part A: Scheduled
Maintenance Services,” in Section
6, for scheduled
rotation
intervals;
After the tires have been rotated, adjust the front and
rear inflation pressures as shown on the
CertificationEire label. Make certain that all wheel nuts
are properly tightened. See “Wheel Nut Torque”
under
Capacities and Specificatiol on ge 5-104.
When rotating your tires, always use the correct rotation
pattern shown here.
Don’t include the spare tire in your tire rotation. Rust or dirt on a
wheel, or on the parts to
which
it is fastened, can make wheel nuts
become loose after a time. The wheel could
come
off and cause an accident. When you
change a wheel, remove any rust or dirt from
places where the wheel attaches to the vehicle,
In an emergency, you can use a cloth or a
paper towel to do
this; but be sure to use a
scraper or wire brush later,
if you need to, to
get all the rust or dirt
off. See “Changing a Flal
Tire”
in the Index.
5-63

When It Is Time for New Tires
One way to tell when it’s
time for new tires is to
check the treadwear
indicators, which will
appear when your tires
have only 1/16 inch
(1.6 mm) or less of tread
remaining. Some
commercial truck tires may
not have treadwear
indicators.
You need a new tire
if any of the following statements
are true:
You can see the indicators at three or more places
You can see cord or fabric showing through the
The tread or sidewall is cracked, cut or snagged
The tire has a bump, bulge or split.
around
the tire.
tire’s rubber.
deep enough to show cord or fabric.
Buying New Tires
To find out what kind and size of tires you need, look at
the Certificationflire label.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specifications (TPC
Spec) number on each tire’s sidewall. When you get
new tires, get ones with that same TPC Spec number.
That way your vehicle will continue to have tires
that are designed to give proper endurance, handling,
speed rating, traction, ride and other things during
normal service on your vehicle.
If your tires have an
all-season tread design, the TPC number will be
followed by an
“MS” (for mud and snow).
If you ever replace your tires with those not having a
TPC Spec number, make sure they are the same size,
load range, speed rating and construction type (bias,
bias-belted or radial) as your original tires.
The tire has a puncture, cut or other damage that
can’t be repaired well because of the size or
location of the damage.
5-64

While the tires available on General Motors passenger
cars and light trucks may vary with respect
to these
grades, they must also conform to federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.
Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specified government test course.
For example, a tire graded
150 would wear one and
a half
(1.5) times as well on the government course as
a tire graded
100. The relative performance of tires
depends upon the actual conditions of their use,
however, and may depart significantly from the norm
due to variations in driving habits, service practices and
differences in road characteristics and climate.
Traction - AA, A, B, C
The traction grades, from highest to lowest, are AA, A,
B, and C. Those grades represent the tire’s ability
to stop on wet pavement as measured under controlled
conditions on specified government test surfaces of
asphalt and concrete.
A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.
Temperature - A, B, C
The temperature grades are A (the highest), B, and C,
representing the tire’s resistance to the generation
of heat and its ability to dissipate heat when tested
under controlled conditions on a specified indoor
laboratory test wheel. Sustained high temperature can
cause the material of the tire to degenerate and
reduce tire life, and excessive temperature can lead to
sudden tire failure. The grade C corresponds
to a
level of performance which all passenger car tires must
meet under the Federal Motor Vehicle Safety Standard
No. 109. Grades B and A represent higher levels of
performance on the laboratory test wheel than the
minimum required by law.
Warning: The temperature grade for this tire is
established for a tire that is properly inflated and not
overloaded. Excessive speed, underinflation, or
excessive loading, either separately or in combination.
can cause heat buildup and possible tire failure.
5-66

Sheet Metal Damage
If your vehicle is damaged and requires sheet metal
repair or replacement, make sure the body repair shop
applies anti-corrosion material to parts repaired
or
replaced to restore corrosion protection.
Original manufacturer replacement parts will provide the
corrosion protection while maintaining the warranty.
Finish Damage
Any stone chips, fractures or deep scratches in the
finish should be repaired right away. Bare metal
will corrode quickly and may develop into major repair
expense.
Minor chips and scratches can be repaired with touch-up
materials avaliable from your dealer or other service
outlets. Larger areas of finish damage can be corrected
in your dealer’s body and paint shop.
Underbody Maintenance
Chemicals used for ice and snow removal and dust
control can collect on the underbody.
If these are not
removed, accelerated corrosion (rust) can occur on
the underbody parts such as fuel lines, frame, floor pan
and exhaust system even though they have corrosion
protection. At
least every spring, flush these materials from the
underbody with plain water. Clean any areas where mud
and debris can collect. Dirt packed in close areas of
the frame should be loosened before being flushed.
Your dealer or an underbody car washing system can
do this for you.
Chemical Paint Spotting
Some weather and atmospheric conditions can create a
chemical fallout. Airborne pollutants can fall upon and
attack painted surfaces on your vehicle. This damage
can take two forms; blotchy, ringlet-shaped
discolorations, and small irregular dark spots etched into
the paint surface.
Although no defect in the paint job causes this,
GM will
repair, at no charge to the owner, the surfaces of
new vehicles damaged by this fallout condition within
12 months or 12,000 miles (20 000 km) of purchase,
whichever occurs first.
5-91

Vehicle Identification
Vehicle Identification Number (VIN)
SAMPLE4UX1 M072675
This is the legal identifier for your vehicle. It appears on
a plate in the front corner of the instrument panel, on
the driver’s side. You can see it
if you look through the
windshield from outside your vehicle. The VIN also
appears on the Vehicle Certification and Service Parts
labels and the certificates of title and registration.
Engine Identification
The 8th character in your VIN is the engine code. This
code will help you identify your engine, specifications
and replacement parts.
Service Parts Identification Label
You’ll find this label located in the glove box. It’s very
helpful
if you ever need to order parts. On this label is:
your VIN,
the model designation,
paint information and
a list of all production options and special
equipment.
Be sure that this label is not removed from the vehicle.
5-94