2005 BUICK CENTURY fuel

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.
Engine Oil Life System
When to Change Engine Oil
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.
5-45

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) or
kilopascals (kPa) before a tire has built up heat
from driving. SeeInation - Tire Pressure on page 5-60.
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 4-31.
GAWR FRT:Gross Axle Weight Rating for the front
axle, seeLoading Your Vehicle on page 4-31.
GAWR RR:Gross Axle Weight Rating for the rear axle,
seeLoading Your Vehicle on page 4-31.
5-57

Ination - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-ination or over-ination is all right. It is not.
If your tires do not have enough air (under-ination),
you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air (over-ination),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazardsA Tire and Loading Information label is attached to the
vehicle’s center pillar (B-pillar), below the driver’s
door latch. This label shows your vehicle’s original
equipment tires and the correct ination pressures for
your tires when they are cold. The recommended
cold tire ination pressure, shown on the label, is the
minimum amount of air pressure needed to support your
vehicle’s maximum load carrying capacity.
For additional information regarding how much weight
your vehicle can carry, and an example of the tire
and loading information label, seeLoading Your Vehicle
on page 4-31. How you load your vehicle affects
vehicle handling and ride comfort, never load your
vehicle with more weight than it was designed to carry.
When to Check
Check your tires once a month or more. Do not forget to
check the compact spare tire, it should be at 60 psi
(420 kPa). For additional information regarding
the compact spare tire, seeCompact Spare Tire on
page 5-81.
5-60

Sheet Metal Damage
If the 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 nish
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 available from your GM dealer. Larger areas
of nish damage can be corrected in your GM
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, 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 GM 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 the 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.
5-88

Relays Usage
15 Not Used
16 Horn
17 Fog Lamps
18 Not Used
19 Fuel Pump
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
Fuses Usage
30 Engine Emissions
31 Fog Lamps
32 Right Headlamp
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
§Air Conditioner Compressor
Clutch Diode
5-95

Capacities and Specications
The following approximate capacities are given in English and metric conversions.
Capacities and Specications
ApplicationCapacities
English Metric
Air Conditioning Refrigerant R134a 2.4 lbs 1.1 kg
Automatic Transaxle
Pan Removal and Replacement
After Complete Overhaul7.4 quarts
10.0 quarts7.0 L
9.5 L
Cooling System Including Reservoir 11.7 quarts 11.0 L
Engine Oil with Filter 4.0 quarts 3.8 L
Fuel Tank 17.0 gallons 64.0 L
Wheel Nut Torque 100 ft lb 140Y
All capacities are approximate. When adding, be sure to ll to the approximate level, as recommended in
this manual.
Engine Specications
Engine VIN Code Transaxle Spark Plug Gap
3100 V6 J Automatic .060 inches (1.52 cm)
5-96

Maintenance Schedule......................................6-2
Introduction...................................................6-2
Maintenance Requirements..............................6-2
Your Vehicle and the Environment....................6-2
Using Your Maintenance Schedule....................6-2
Scheduled Maintenance...................................6-4
Additional Required Services............................6-6
Maintenance Footnotes...................................6-8Owner Checks and Services............................6-9
At Each Fuel Fill............................................6-9
At Least Once a Month.................................6-10
At Least Once a Year...................................6-10
Recommended Fluids and Lubricants...............6-13
Normal Maintenance Replacement Parts..........6-14
Engine Drive Belt Routing..............................6-15
Maintenance Record.....................................6-16
Section 6 Maintenance Schedule
6-1