2003 GMC SIERRA DENALI fuel cap

6. 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
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.
5-36

Inflation - Tire Pressure
The CertificationKire label, which is on the rear edge of
the driver’s door, shows the correct inflation pressures
for your tires when they’re cold. “Cold” means your
vehicle has been sitting for at least three hours or driven
no more than
1 mile (1.6 km).
Notice: Don’t let anyone tell you that underinflation
or overinflation is all right. It’s not. If your tires
don’t have enough air (underinflation), you can get
the following:
Too much flexing
Too much heat
Tire overloading
Bad wear
Bad handling
Bad fuel economy
If your tires have too much air (overinflation), you
can get the following:
Unusual wear
Bad handling
Rough ride
Needless damage from road hazards
5-62
When to Check
Check your tires once a month or more.
Also, check the tire pressure of the spare tire
How to Check
Use a good quality pocket-type gage to check tire
pressure. You can’t tell
if your tires are properly inflated
simply by looking at them. Radial tires may look
properly inflated even when they’re underinflated.
Be sure to put the valve caps back on the valve stems.
They help prevent leaks by keeping out dirt and
moisture.
Tire Inspection and Rotation
Tires should be rotated every 7,500 miles (12,500 km).
Any time you notice unusual wear, rotate your tires
as soon as possible and check wheel alignment.
Also
check for damaged tires or wheels. See When It Is Time
for New Tires on page 5-64 and Wheel Replacement
on page
5-67 for more information.
Make sure the spare tire
is stored securely. Push, pull,
and then try to rotate
or turn the tire. If it moves,
use the wheel wrench and jack handle extensions to
tighten the cable. See
Changing a Flat Tire on
page
5-69.

Capacities and Specifications
Capacities and Specifications
Capacities
Application
All capacities are approximate. When adding, be sure to
fill to the approximate level, as recommended in this
Use
Refrigerant Oil, R134a Systems 0.8
kg
1.76 Ibs.
Air Conditioning Refrigerant R134a 98.4
L 26.0 gallons
Fuel
Tank 5.7
L 6.0 quarts
Engine Oil
with Filter 14.0
L 14.8 quarts
Cooling
System Metric
English
manual. See
Part D: Recommended Fluids and Lubricants on page 6-16.
Engine Specifications
Engine Spark Plug Gap
Type
VIN Code
VORTEC 6000
0.060 inches (1.52 mm) V8
U
Wheels and Tires
Wheel Nut Torque
See the CertificationKire label on the rear edge of the
Tire
Pressure 140 Ib ft (190 N*m )
driver’s door.
5-1 04

90,000 Miles (150 000 km)
0 Check readfront axle fluid level and add fluid as
needed. Check constant velocity joints and axle seals
for leaking.
0 Replace fuel filter. An Emission Control Service. (See
Footnote
t.)
0 Replace engine air cleaner filter. An Emission
Control Service.
0 Rotate tires. See Tire Inspection and Rotation on
page 5-62
for proper rotation pattern and additional
information.
(See footnote +.)
97,500 Miles (162 500 km)
c[I Check readfront axle fluid level and add fluid as
needed. Check constant velocity joints and axle seals
for leaking.
page 5-62 for proper rotation pattern and additional
information.
(See footnote +.)
0 Rotate tires. See Tire Inspection and Rotation on
100,000 Miles (166 000 km)
0 Inspect spark plug wires. An Emission Control
0 Replace spark plugs. An Emission Control Service.
Service.
0 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.
0 If you haven’t used your vehicle under severe service
conditions listed previously and, therefore, haven’t
changed your automatic transmission fluid, change
both the fluid and filter.
0 Inspect Positive Crankcase Ventilation (PCV) valve.
An Emission Control Service.
150,000 Miles (240 000 km)
0 Drain, flush and refill cooling system (or every
60 months since last service, whichever occurs first).
See
Engine Coolant on page 5-24 for what to use.
Inspect hoses. Clean radiator, condenser, pressure
cap and neck. Pressure test the cooling system
and pressure cap.
An Emission Control Service.
0 Inspect engine accessory drive belt. An Emission
Control Service.
6-9

Part C: Periodic Maintenance
Inspections
Listed in this part are inspections and services which
should be performed at least twice a year (for instance,
each spring and fall).
You should let your dealer’s
service department or other qualified service center do
these jobs. Make sure any necessary repairs are
completed at once.
Proper procedures to perform these services may be
found in a service manual. See
Service Publications
Ordering lnformation on page
7- 10.
Steering and Suspension Inspection
Inspect the front and rear suspension and steering
system for damaged, loose or missing parts, signs of
wear or lack of lubrication. Inspect the power steering
lines and hoses for proper hook-up, binding, leaks,
cracks, chafing, etc.
Exhaust System Inspection
Inspect the complete exhaust system. Inspect the body
near the exhaust system. Look for broken, damaged,
missing or out-of-position parts as well as open seams,
holes, loose connections or other conditions which
could cause a heat build-up in the floor pan or could let
exhaust fumes into the vehicle. See
Engine Exhaust
on page
2-26.
Fuel System Inspection
Inspect the complete fuel system for damage or leaks.
Engine Cooling System Inspection
Inspect the hoses and have them replaced if they
are cracked, swollen or deteriorated. Inspect
all pipes,
fittings and clamps; replace as needed. Clean the
outside of the radiator and air conditioning condenser.
To help ensure proper operation, a pressure test of
the cooling system and pressure cap is recommended
at least once a year.
6-1 4

Audio Systems (cont.)
XMTM Satellite Radio Antenna System ............ 3-84
Automatic Headlamp System
............................ 3-1 2
Operation ................................................... 2-1 8
System Check
......................................... 6-12
Automatic
Transmission
Fluid
.......................................................... 5-21
Automatic Transmission Check
.......................... 6-1 1
Automatic Transmission Shift Lock Control
B
Backing Up .................................................... 4-57
Battery
.......................................................... 5-42
Battery Replacement
......................................... 2-5
Battery Run-Down Protection ............................ 3-1 6
BATTERY NOT CHARGING
............................. 3-54
Battery Warning Light
...................................... 3-33
Before Leaving on a Long Trip
......................... 4-35
Body Lubrication Service
.................................. 6-1 1
Brake Parking
...................................................... 2-22
System Inspection
....................................... 6-1 5
System Warning Light .................................. 3-34
Brake Adjustment
............................................ 5-42
Brake Fluid
.................................................... 5-39
Brake Pedal Travel
......................................... 5-42
Brake Wear
.................................... ....... 5-41
Brakes
.......................................................... 5-39
Braking ........................................................... 4-6 Braking
in Emergencies
..................................... 4-8
Break-In, New Vehicle
..................................... 2-15
Bulb Replacement
........................................... 5-52
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp
............................................ 5-56
Front Turn Signal, Sidemarker and Daytime
Running Lamps
........................................ 5-53
Halogen Bulbs
............................................ 5-52
Headlamps
................................................. 5-52
Pickup Box Identification and Fender
Marker Lamps
......................................... 5-58
Replacement Bulbs
...................................... 5-59
Roof Marker Lamps
..................................... 5-54
Buying New Tires
........................................... 5-64
Taillamps
.................................................... 5-58
C
California Fuel .................................................. 5-6
Canada
........................................................... 7-4
Canadian Owners
................................................ ii
Canadian Roadside Assistance ........................... 7-7
Capacities and Specifications
.......................... 5-1 04
Car Washes for QUADRASTEERTM Equipped Vehicles
..................................................... 4-13
Carbon Monoxide
..................... 4-38, 4-51, 2-8, 2-26
Care of
Safety Belts
................................ ..... 5-88
Care
of Your
Cassette Tape Player
................................... 3-83
2