2004 BUICK CENTURY fuel

A. Windshield Washer Fluid Reservoir. SeeWindshield
Washer Fluid on page 5-36.
B. Battery. SeeBattery on page 5-41.
C. Underhood Fuse Block. SeeFuses and Circuit
Breakers on page 5-97.
D. Remote Positive (+) Battery Terminal. SeeJump
Starting on page 5-42.
E. Radiator Pressure Cap. SeeRadiator Pressure Cap
on page 5-25.
F. Engine Coolant Recovery Tank. SeeEngine Coolant
on page 5-22.
G. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-35.
H. Electric Engine Cooling Fan. SeeJump Starting on
page 5-42.
I. Engine Oil Fill Cap. SeeEngine Oil on page 5-13.
J. Engine Oil Dipstick. SeeEngine Oil on page 5-13.
K. Automatic Transaxle Fluid Dipstick. SeeAutomatic
Transaxle Fluid on page 5-19.
L. Brake Fluid Reservoir. SeeBrakes on page 5-38.
M. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-18.Engine Oil
Checking Engine Oil
It is a good idea to check your engine oil every time you
get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop. See
Engine Compartment Overview on page 5-12for
the location of the engine oil dipstick.
Turn off the engine and give the oil several minutes to
drain back into the oil pan. If you don’t, the oil
dipstick might not show the actual level.
Pull out the dipstick and clean it with a paper towel or
cloth, then push it back in all the way. Remove it again,
keeping the tip down, and check the level.
5-13

Notice:Use only engine oil identied as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certied For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.
GM Goodwrench
®oil meets all the requirements for
your vehicle.
If you are in an area of extreme cold, where the
temperature falls below−20°F (−29°C), it is
recommended that you use either an
SAE 5W-30 synthetic oil or an SAE 0W-30 oil. Both will
provide easier cold starting and better protection for
your engine at extremely low temperatures.
Engine Oil Additives
Do not add anything to your oil. The recommended oils
with the starburst symbol that meet GM Standard
GM6094M are all you will need for good performance
and engine protection.
When to Change Engine Oil
(GM Oil Life System)
Your vehicle has a computer system that lets you know
when to change the engine oil and lter. This is
based on engine revolutions and engine temperature,
and not on mileage. Based on driving conditions,
the mileage at which an oil change will be indicated can
vary considerably. For the oil life system to work
properly, you must reset the system every time the oil is
changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE OIL SOON light will come on.
Change your oil as soon as possible within the next
two times you stop for fuel. It is possible that, if you are
driving under the best conditions, the oil life system
may not indicate that an oil change is necessary for over
a year. However, your engine oil and lter must be
changed at least once a year and at this time the system
must be reset. Your dealer has GM-trained service
people who will perform this work using genuine GM
parts and reset the system. It is also important to check
your oil regularly and keep it at the proper level.
If the system is ever reset accidentally, you must change
your oil at 3,000 miles (5 000 km) since your last oil
change. Remember to reset the oil life system whenever
the oil is changed.
5-16

Headlamp Aiming
The vehicle has a headlamp system equipped with
horizontal and vertical aim indicators. The aim has been
pre-set at the factory and should need no further
adjustment. This is true even though the vertical and
horizontal aim indicators may not fall exactly on
the “0” (zero) marks on their scales.
If the vehicle is damaged in an accident, the headlamp
aim may be affected. Aim adjustment may be
necessary if it is difficult to see lane markers, for
horizontal aim, or if oncoming drivers ash their high
beams at you, for vertical aim. If you believe the
headlamps need to be re-aimed, we recommend that
you take it to your dealer for service; however, it is
possible for you to re-aim the headlamps as described
in the following procedure.
Notice:To make sure your headlamps are aimed
properly, read all the instructions before beginning.
Failure to follow these instructions could cause
damage to headlamp parts.To check the aim, the vehicle should be properly
prepared as follows:The headlamps must be off for one hour prior to
aiming and must remain off during this procedure.
The vehicle must have all four tires on a perfectly
level surface.
If necessary, pads may be used on an uneven
surface to help level the vehicle.
The vehicle should not have any snow, ice or mud
attached to it.
The vehicle should be fully assembled and all other
work stopped while headlamp aiming is being done.
There should not be any cargo or loading of
the vehicle. It should however, have a full fuel
tank and one person or 160 lbs (75 kg) on
the driver’s seat.
Close all doors.
Tires should be properly inated.
Rock the vehicle to stabilize the suspension.
5-49

Tire Terminology and Denitions
Air Pressure:The amount of air inside the tire pressing
outward on each square inch of the tire. Air pressure
is expressed in pounds per square inch (psi) or
kilopascal (kPa).
Accessory Weight:This means the combined weight
of optional accessories. Some examples of optional
accessories are, automatic transmission, power steering,
power brakes, power windows, power seats, and air
conditioning.
Aspect Ratio:The relationship of a tire’s height to
its width.
Belt:A rubber coated layer of cords that is located
between the plies and the tread. Cords may be made
from steel or other reinforcing materials.
Bead:The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the rim.
Bias Ply Tire:A pneumatic tire in which the plies are
laid at alternate angles less than 90 degrees to the
centerline of the tread.
Cold Ination Pressure:The amount of air pressure
in a tire, measured in pounds per square inch (psi)
before a tire has built up heat from driving.
SeeInation - Tire Pressure on page 5-64.Curb Weight:This means the weight of a motor
vehicle with standard and optional equipment including
the maximum capacity of fuel, oil and coolant, but
without passengers and cargo.
DOT Markings:A code molded into the sidewall of a
tire signifying that the tire is in compliance with the U.S.
Department of Transportation motor vehicle safety
standards. The DOT code includes the Tire Identication
Number (TIN), an alphanumeric designator which can
also identify the tire manufacturer, production plant,
brand and date of production.
GVWR:Gross Vehicle Weight Rating, seeLoading
Your Vehicle on page 4-34.
GAWR FRT:Gross Axle Weight Rating for the front
axle, seeLoading Your Vehicle on page 4-34.
GAWR RR:Gross Axle Weight Rating for the rear axle,
seeLoading Your Vehicle on page 4-34.
Intended Outboard Sidewall:The side of an
asymmetrical tire that must always face outward when
mounted on a vehicle.
Kilopascal (kPa):The metric unit for air pressure.
There are 6.9 kPa’s to one psi.
Light Truck (LT-Metric) Tire:A tire used on light duty
trucks and some multipurpose passenger vehicles.
5-62

Treadwear Indicators:Narrow bands, sometimes
called “wear bars,” that show across the tread of a tire
when only 2/32 inch of tread remains. SeeWhen It
Is Time for New Tires on page 5-68.
UTQGS:Uniform Tire Quality Grading Standards, a tire
information system that provides consumers with
ratings for a tire’s traction, temperature and treadwear.
Ratings are determined by tire manufacturers using
government testing procedures. The ratings are molded
into the sidewall of the tire. SeeUniform Tire Quality
Grading on page 5-70.
Vehicle Capacity Weight:The number of designated
seating positions multiplied by 150 lbs. (68 kg) plus
the rated cargo load. SeeLoading Your Vehicle
on page 4-34.
Vehicle Maximum Load on the Tire:Load on an
individual tire due to curb weight, accessory weight,
occupant weight and cargo weight.
Vehicle Placard:A label permanently attached to a
vehicle showing the original equipment tire size
and recommended ination pressure. SeeLoading Your
Vehicle on page 4-34.Ination - Tire Pressure
The tire and loading information label, shows the correct
ination 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). See
Loading Your Vehicle on page 4-34, for the location
of your vehicle’s tire and loading information label.
Notice:Don’t let anyone tell you that underination
or overination is all right. It’s not. If your tires
don’t have enough air (underination), you can get
the following:
Too much exing
Too much heat
Tire overloading
Bad wear
Bad handling
Bad fuel economy
If your tires have too much air (overination), you
can get the following:
Unusual wear
Bad handling
Rough ride
Needless damage from road hazards
5-64

Underbody Maintenance
Chemicals used for ice and snow removal and dust
control can collect on the underbody. If these are not
removed, corrosion and rust can develop on the
underbody parts such as fuel lines, frame, oor pan and
exhaust system even though they have corrosion
protection.
At least every spring, ush 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 ushed.
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, ring-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 rst.
5-94

Fuses Usage
1 Anti-Lock Brake System
2 Starter Solenoid
3 Power Seat, Rear Window Defogger
4High Blower, Hazard Flasher,
Stoplamps, Power Mirror,
Door Locks
5Ignition Switch, Stoplamps,
Anti-Lock Brake System, Turn
Signals, Cluster, Air Bag, Daytime
Running Lamps Module
6 Cooling Fan
7Retained Accessory Power, Remote
Keyless Entry, Data Link, Heating,
Ventilation, and Air Conditioning
Head; Cluster, Radio, Cigarette
Lighter
8Ignition Switch, Wipers, Autdio
Steering Wheel Controls, Body
Control Module, Power Windows,
Sunroof, Heating, Ventilation, and
Air Conditioning Controls; Daytime
Running Lamps, Rear Window
Defogger RelayRelays Usage
9 Cooling Fan 2
10 Cooling Fan 3
11 Starter Solenoid
12 Cooling Fan 1
13 Ignition Main
14 Air Pump (Optional)
15 Not Used
16 Horn
17 Fog Lamps
18 Not Used
19 Fuel Pump
5-101

Fuses Usage
20 Not Used
21 Generator
22 Engine Control Module
23 Air Conditioner Compressor Clutch
24 Cooling Fan
25 Electronic Ignition
26 Transaxle
27 Horn
28 Fuel Injector
29 Oxygen Sensor
30 Engine Emissions
31 Fog Lamps
32 Right HeadlampFuses Usage
33 Rear Compartment Release
34 Parking Lamps
35 Fuel Pump
36 Left Headlamp
37 Not Used
38 Not Used
39 Not Used
40 Not Used
41 Not Used
42 Not Used
43 Not Used
SYMBOLAir Conditioner Compressor
Clutch Diode
5-102