2003 BUICK CENTURY check engine

Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside
of Your Vehicle...........................................5-4
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Speci®cations....................................5-5
California Fuel...............................................5-6
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling Your Tank............................................5-7
Filling a Portable Fuel Container.......................5-9
Checking Things Under the Hood....................5-10
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-13
Engine Air Cleaner/Filter................................5-18
Automatic Transaxle Fluid..............................5-19
Engine Coolant.............................................5-23
Radiator Pressure Cap..................................5-26
Engine Overheating.......................................5-26
Cooling System............................................5-29
Power Steering Fluid.....................................5-36
Windshield Washer Fluid................................5-38
Brakes........................................................5-39Battery........................................................5-42
Jump Starting...............................................5-43
Headlamp Aiming...........................................5-49
Bulb Replacement..........................................5-51
Halogen Bulbs..............................................5-51
Headlamps..................................................5-51
Front Turn Signal and Parking Lamps..............5-52
Center High-Mounted Stoplamp (CHMSL).........5-53
Taillamps, Turn Signal, and Stoplamps............5-54
Back-Up Lamps............................................5-55
Replacement Bulbs.......................................5-55
Windshield Wiper Blade Replacement..............5-56
Tires..............................................................5-57
In¯ation Ð Tire Pressure...............................5-57
Tire Pressure Monitor System.........................5-58
Tire Inspection and Rotation...........................5-60
When It Is Time for New Tires.......................5-61
Buying New Tires.........................................5-62
Uniform Tire Quality Grading..........................5-63
Wheel Alignment and Tire Balance..................5-64
Wheel Replacement......................................5-64
Tire Chains..................................................5-66
If a Tire Goes Flat........................................5-66
Changing a Flat Tire.....................................5-67
Compact Spare Tire......................................5-78
Section 5 Service and Appearance Care
5-1

California Fuel
If your vehicle is certi®ed to meet California Emission
Standards (see the underhood emission control label), it
is designed to operate on fuels that meet California
speci®cations. If this fuel is not available in states
adopting California emissions standards, your vehicle
will operate satisfactorily on fuels meeting federal
speci®cations, but emission control system performance
may be affected. The malfunction indicator lamp may
turn on (see
Malfunction Indicator Lamp on page 3-31)
and your vehicle may fail a smog-check test. If this
occurs, return to your authorized GM dealer for
diagnosis. If it is determined that the condition is caused
by the type of fuel used, repairs may not be covered
by your warranty.
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 speci®cations 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.
5-6

Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard
to ®nd. 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't be
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.
Filling Your Tank
{CAUTION:
Fuel vapor burns violently and a fuel ®re can
cause bad injuries. To help avoid injuries to you
and others, read and follow all the instructions
on the pump island. Turn off your engine when
you are refueling. Don't smoke if you're near
fuel or refueling your vehicle. Keep sparks,
¯ames and smoking materials away from fuel.
CAUTION: (Continued)
CAUTION: (Continued)
Don't leave the fuel pump unattended when
refueling your vehicle Ð this is against the law
in some places. Keep children away from the
fuel pump; never let children pump fuel.
Turn your vehicle off to refuel.
The tethered fuel cap is located behind a hinged door
on the driver's side of the vehicle.
5-7

Checking Things Under the
Hood
{CAUTION:
An electric fan under the hood can start up
and injure you even when the engine is not
running. Keep hands, clothing and tools away
from any underhood electric fan.
{CAUTION:
Things that burn can get on hot engine parts
and start a ®re. These include liquids like fuel,
oil, coolant, brake ¯uid, windshield washer and
other ¯uids, and plastic or rubber. You or
others could be burned. Be careful not to drop
or spill things that will burn onto a hot engine.
5-10

A. Windshield Washer Fluid Reservoir. SeeWindshield
Washer Fluid on page 5-38.
B. Battery. See
Battery on page 5-42.
C. Underhood Fuse Block. See
Fuses and Circuit
Breakers on page 5-89.
D. Remote Positive (+) Battery Terminal. See
Jump
Starting on page 5-43.
E. Radiator Pressure Cap. See
Radiator Pressure Cap
on page 5-26.
F. Engine Coolant Recovery Tank. See
Engine Coolant
on page 5-23.
G. Power Steering Fluid Reservoir. See
Power Steering
Fluid on page 5-36.
H. Electric Engine Cooling Fan. See
Jump Starting on
page 5-43.
I. Engine Oil Fill Cap. See
Engine Oil on page 5-13.
J. Engine Oil Dipstick. See
Engine Oil on page 5-13.
K. Automatic Transaxle Fluid Dipstick. See
Automatic
Transaxle Fluid on page 5-19.
L. Brake Fluid Reservoir. See
Brakes on page 5-39.
M. Engine Air Cleaner/Filter. See
Engine Air
Cleaner/Filter on page 5-18.
Engine Oil
Checking Engine Oil
It's 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 the yellow loop
located near the front
of the engine. See
Engine
Compartment Overview
on page 5-12
for more
information on location.
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.
5-13

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.
When to Add Engine Oil
If the oil is at or below the cross-hatched area at the tip
of the dipstick, then you'll need to add at least one
quart of oil. But you must use the right kind. This part
explains what kind of oil to use. For engine oil crankcase
capacity, see
Capacities and Speci®cations on
page 5-94.
Notice:Don't add too much oil. If your engine has
so much oil that the oil level gets above the
cross-hatched area that shows the proper operating
range, your engine could be damaged.The engine oil ®ll cap is
located toward the front of
the engine near the
engine oil dipstick handle.
See
Engine Compartment
Overview on page 5-12
for more information
on location.
Be sure to ®ll it enough to put the level somewhere in the
proper operating range in the cross-hatched area. Push
the dipstick all the way back in when you're through.
5-14

As in the chart shown previously, SAE 5W-30 is the
only viscosity grade recommended for your vehicle. You
should look for and use only oils which have the API
Starburst symbol and which are also identi®ed as
SAE 5W-30. If you cannot ®nd such SAE 5W-30 oils,
you can use an SAE 10W-30 oil which has the API
Starburst symbol, if it's going to be 0ÉF (-18ÉC)
or above. Do not use other viscosity grade oils, such as
SAE 10W-40 or SAE 20W-50 under any conditions.
Notice:Use only engine oil with the American
Petroleum Institute Certi®ed For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.
GM Goodwrench
žoil meets all the requirements for
your vehicle.
If you are in an area of extreme cold, where the
temperature falls below-20ÉF (-29ÉC), 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
Don't add anything to your oil. The recommended oils
with the starburst symbol 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

Engine Air Cleaner/Filter
SeeEngine Compartment Overview on page 5-12for
location of engine air cleaner/®lter.
When to Inspect
Inspect the air cleaner/®lter every 15,000 miles
(25,000 km) and replace every 30,000 miles
(50,000 km). If you are driving in dusty/dirty conditions,
inspect the ®lter at each engine oil change.
How to Inspect
To inspect the air cleaner/®lter remove it from the
vehicle andlightlyshake the ®lter to release loose dust
and dirt. If the ®lter remains ªcakedº with dirt, a new
®lter is required.
To check or replace the engine air cleaner/®lter, do the
following:
1. Loosen the screw and clamp on the air duct.2. Lift up on the two clips
located on the top of
the ®lter assembly
to unlock the cover.
3. Disconnect the duct and reposition it while removing
the cover.
4. Pull out the ®lter.
5. Inspect or replace the ®lter if needed.
6. Reinstall the ®lter.
7. Push down on the two clips located on top of the
®lter assembly to lock the cover.
5-18