2003 GMC SIERRA fuel lines

Passlock®
Your vehicle is equipped with the
Passlock®theft-deterrent system.
Passlock
®is a passive theft-deterrent system.
Passlock®enables fuel if the ignition lock cylinder is
turned with a valid key. If a correct key is not used or the
ignition lock cylinder is tampered with, fuel is disabled.
If the engine stalls and the security lightashes,
wait until the light stopsashing before trying to restart
the engine. Remember to release the key from
START as soon as the engine starts.
If the engine is running and the security light comes on,
you will be able to restart the engine if you turn the
engine off. However, your Passlock
®system is
not working properly and must be serviced by your
dealer. Your vehicle is not protected by Passlock
®at this
time. You may also want to check the fuse (see
Fuses and Circuit Breakers on page 5-91.) See your
dealer for service.
In an emergency, call the GM Roadside Assistance
Center. SeeRoadside Assistance Program on page 7-5
under Customer Assistance Information.
Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle doesn’t need an elaborate
“break-in.”But it will perform better in the long run
if you follow these guidelines:
Keep your speed at 55 mph (88 km/h) or less for
the first 500 miles (805 km).
•Don’t drive at any one speed — fast or
slow — for the first 500 miles (805 km).
Don’t make full-throttle starts.
•Avoid making hard stops for the first 200 miles
(322 km) or so. During this time your new
brake linings aren’t yet broken in. Hard stops
with new linings can mean premature wear and
earlier replacement. Follow this breaking-in
guideline every time you get new brake linings.
•Don’t tow a trailer during break-in. See “Towing
a Trailer” in the Index for more information.
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2003 - Sierra Denali

After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis or under the hood. These
accumulations can be are hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, wheels, tires and exhaust
system for damage. Also, check the fuel lines and
cooling system for any leakage.
Your vehicle will require more frequent service due to
off-road use. Refer to the Maintenance Schedule
for additional information.
Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to be
impaired—by alcohol or drugs, with night vision
problems, or by fatigue.
Here are some tips on night driving.
Drive defensively.
Don’t drink and drive.
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2003 - Sierra Denali

Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work
properly. You should not have to add anything to your
fuel. Gasolines containing oxygenates, such as
ethers and ethanol, and reformulated gasolines may be
available in your area to contribute to clean air.
General Motors recommends that you use these
gasolines, particularly if they comply with the
specifications described earlier.
Notice:Your vehicle was not designed for fuel that
contains methanol. Don’t use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage wouldn’t be covered under your
warranty.Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors does
not recommend the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs and
the performance of the emission control system may
be affected. The malfunction indicator lamp may turn on.
If this occurs, return to your authorized GM dealer for
service.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard
tofind. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel wouldn’tbe
covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you’ll be driving.
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2003 - Sierra Denali

Cleaning Aluminum or Chrome-Plated
Wheels
Your vehicle may be equipped with either aluminum or
chrome-plated wheels.
Keep your wheels clean using a soft clean cloth with
mild soap and water. Rinse with clean water. After
rinsing thoroughly, dry with a soft clean towel. A wax
may then be applied.
The surface of these wheels is similar to the painted
surface of your vehicle. Don’t use strong soaps,
chemicals, abrasive polishes, abrasive cleaners,
cleaners with acid, or abrasive cleaning brushes on
them because you could damage the surface. Do not
use chrome polish on aluminum wheels.
Use chrome polish only on chrome-plated wheels, but
avoid any painted surface of the wheel, and buff off
immediately after application.
Don’t take your vehicle through an automatic car wash
that has silicone carbide tire cleaning brushes. These
brushes can also damage the surface of these wheels.
Cleaning Tires
To clean your tires, use a stiff brush with tire cleaner.
Notice:When applying a tire dressing, always take
care to wipe off any overspray or splash from all
painted surfaces on the body or wheels of the
vehicle. Petroleum-based products may damage the
paintfinish and tires.
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. 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.
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2003 - Sierra Denali

60,000 Miles (100 000 km)
❑Inspect engine air cleanerlter change indicator.
If necessary, replace thelter. If vehicle is driven
in dusty/dirty conditions, inspectlter change
indicator at every engine oil change. SeeEngine Air
Cleaner/Filter on page 5-18for more information.
An Emission Control Service. (See footnote†.)
❑Check rear/front axleuid level and adduid as
needed. Check constant velocity joints and axle seals
for leaking.
❑Rotate tires. SeeTire Inspection and Rotation on
page 5-58for proper rotation pattern and additional
information.(See footnote +.)
❑Replace fuellter.An Emission Control Service.
(See footnote†.)
❑Inspect Evaporative Control 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.
An Emission Control Service. (See footnote†.)
67,500 Miles (112 500 km)
❑Check rear/front axleuid level and adduid as
needed. Check constant velocity joints and axle seals
for leaking.
❑Rotate tires. SeeTire Inspection and Rotation on
page 5-58for proper rotation pattern and additional
information.(See footnote +.)
75,000 Miles (125 000 km)
❑Inspect engine air cleanerlter change indicator.
If necessary, replace thelter. If vehicle is driven
in dusty/dirty conditions, inspectlter change
indicator at every engine oil change. SeeEngine Air
Cleaner/Filter on page 5-18for more information.
An Emission Control Service. (See footnote†.)
❑Check rear/front axleuid level and adduid as
needed. Check constant velocity joints and axle seals
for leaking.
❑Rotate tires. SeeTire Inspection and Rotation on
page 5-58for proper rotation pattern and additional
information.(See footnote +.)
82,500 Miles (137 500 km)
❑Check rear/front axleuid level and adduid as
needed. Check constant velocity joints and axle seals
for leaking.
❑Rotate tires. SeeTire Inspection and Rotation on
page 5-58for proper rotation pattern and additional
information.(See footnote +.)
90,000 Miles (150 000 km)
❑Inspect engine air cleanerlter change indicator.
If necessary, replace thelter. If vehicle is driven
in dusty/dirty conditions, inspectlter change
indicator at every engine oil change. SeeEngine Air
Cleaner/Filter on page 5-18for more information.
An Emission Control Service. (See footnote†.)
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2003 - Sierra Denali

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 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. SeeService Publications
Ordering Information on page 7-9.
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, chang, 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 theoor pan or could let
exhaust fumes into the vehicle. SeeEngine 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,
ttings 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.
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2003 - Sierra Denali

Usage Fluid/Lubricant
Key Lock
CylindersMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474, or equivalent).
Floor Shift
LinkageLubriplate Lubricant Aerosol (GM
Part No. U.S. 12346293, in Canada
992723, or equivalent) or lubricant
meeting requirements of NLGI #2
Category LB or GC-LB.
Chassis
LubricationChassis Lubricant (GM Part No.
U.S. 12377985, in Canada
88901242, or equivalent) or lubricant
meeting requirements of NLGI #2,
Category LB or GC-LB.
Front AxleSAE 75W-90 Synthetic Axle
Lubricant (GM Part No. U.S.
12378261, in Canada 10953455) or
equivalent meeting GM Specication
9986115.
Rear Axle
(Steerable)Synthetic Axle Lubricant; use only
GM Part No. 12378557 (in Canada
88901362). Do not add friction
modier.
Transfer CaseDEXRON
®-III Automatic
Transmission Fluid.
Rear Driveline
Center SplineChassis Lubricant (GM Part No.
U.S. 12377985, in Canada
88901242, or equivalent) or lubricant
meeting requirements of NLGI #2,
Category LB or GC-LB.
Usage Fluid/Lubricant
Front Axle
Propshaft
SplineSpline Lubricant, Special Lubricant
(GM Part No. U.S. 12345879, in
Canada 10953511) or lubricant
meeting requirements of GM
9985830.
Hood HingesMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474, or equivalent).
Body Door
Hinge Pins,
Tailgate Hinge
and Linkage,
Folding Seats
and Fuel Door
HingeMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474, or equivalent).
Tailgate Handle
Pivot Points,
Hinges, Latch
Bolt and
LinkageMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474, or equivalent).
Weatherstrip
ConditioningDielectric Silicone Grease (GM Part
No. U.S. 12345579, in Canada
10953014, or equivalent).
Weatherstrip
SqueaksSynthetic Grease with Teon,
Superlube (GM Part No. U.S.
12371287, in Canada 10953437, or
equivalent).
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2003 - Sierra Denali