engine BUICK CENTURY 2003 Workshop Manual

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

What Kind of Engine Oil to Use
Oils recommended for your vehicle can be identi®ed by
looking for the starburst symbol.
This symbol indicates that the oil has been certi®ed by
the American Petroleum Institute (API). Do not use
any oil which does not carry this starburst symbol.
If you choose to perform
the engine oil change
service yourself, be sure
the oil you use has the
starburst symbol on the
front of the oil container. If
you have your oil changed
for you, be sure the oil put
into your engine is
American Petroleum
Institute certi®ed for
gasoline engines.
You should also use the proper viscosity oil for your
vehicle, as shown in the viscosity chart.
5-15

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

How to Reset the CHANGE OIL SOON
Light
The GM Oil Life System calculates when to change
your engine oil and ®lter based on vehicle use. Anytime
your oil is changed, reset the system so it can
calculate when the next oil change is required. If a
situation occurs where you change your oil prior to a
CHANGE OIL SOON light being turned on, reset
the system.
After changing the engine oil, reset the system by
performing the following steps:
1. With the engine off, turn the ignition key to RUN.
2. Fully push and release the accelerator pedal slowly
three times within ®ve seconds.
If the CHANGE OIL SOON light ¯ashes, the system
is resetting.
3. Turn the key to OFF, then start the vehicle. The oil
life will change to 100 percent.
If the CHANGE OIL SOON light comes back on, the
system has not reset. Repeat the procedure.
What to Do with Used Oil
Used engine oil contains certain elements that may be
unhealthy for your skin and could even cause cancer.
Don't let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good
hand cleaner. Wash or properly dispose of clothing or
rags containing used engine oil. See the manufacturer's
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
®lter before disposal. Never dispose of oil by putting it
in the trash, pouring it on the ground, into sewers, or into
streams or bodies of water. Instead, recycle it by
taking it to a place that collects used oil. If you have a
problem properly disposing of your used oil, ask
your dealer, a service station or a local recycling center
for help.
5-17

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

{CAUTION:
Operating the engine with the air cleaner/®lter
off can cause you or others to be burned. The
air cleaner not only cleans the air, it helps to
stop ¯ame if the engine back®res. If it isn't there
and the engine back®res, you could be burned.
Don't drive with it off, and be careful working on
the engine with the air cleaner/®lter off.
Notice:If the air cleaner/®lter is off, a back®re can
cause a damaging engine ®re. And, dirt can
easily get into your engine, which will damage it.
Always have the air cleaner/®lter in place when
you're driving.
Automatic Transaxle Fluid
When to Check and Change
A good time to check your automatic transaxle ¯uid
level is when the engine oil is changed.
Change both the ¯uid and ®lter every 50,000 miles
(83 000 km) if the vehicle is mainly driven under one or
more of these conditions:
·In heavy city traffic where the outside temperature
regularly reaches 90ÉF (32ÉC) or higher.
·In hilly or mountainous terrain.
·When doing frequent trailer towing.
·Uses such as found in taxi, police or delivery
service.
If you do not use your vehicle under any of these
conditions, change the ¯uid and ®lter at 100,000 miles
(166 000 km).
See
Part A: Scheduled Maintenance Services on
page 6-4.
5-19

How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice:Too much or too little ¯uid can damage
your transaxle. Too much can mean that some of the
¯uid could come out and fall on hot engine or
exhaust system parts, starting a ®re. Too little ¯uid
could cause the transaxle to overheat. Be sure
to get an accurate reading if you check your
transaxle ¯uid.
Wait at least 30 minutes before checking the transaxle
¯uid level if you have been driving:
·When outside temperatures are above 90ÉF (32ÉC).
·At high speed for quite a while.
·In heavy traffic ± especially in hot weather.
·While pulling a trailer.To get the right reading, the ¯uid should be at normal
operating temperature, which is 180ÉF to 200ÉF
(82ÉC to 93ÉC).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50ÉF
(10ÉC). If it's colder than 50ÉF (10ÉC), you may have to
drive longer.
5-20

Checking the Fluid Level
Prepare your vehicle as follows:
·Park your vehicle on a level place. Keep the engine
running.
·With the parking brake applied, place the shift lever
in PARK (P).
·With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK (P).
·Let the engine run at idle for three to ®ve minutes.Then, without shutting off the engine, follow these steps:
The automatic transaxle
¯uid dipstick handle is the
black loop located
toward the rear of the
engine. See
Engine
Compartment Overview on
page 5-12
for more
information on location.
1. Pull out the dipstick and wipe it with a clean rag or
paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again.
5-21

Engine Coolant
The cooling system in your vehicle is ®lled with
DEX-COOLžengine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs ®rst, if you add
only DEX-COOL
žextended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating or if you need to add coolant to
your radiator, see
Engine Overheating on page 5-26.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
žcoolant will:
·Give freezing protection down to-34ÉF (-37ÉC).
·Give boiling protection up to 265ÉF (129ÉC).
·Protect against rust and corrosion.
·Help keep the proper engine temperature.
·Let the warning lights and gages work as they
should.
Notice:When adding coolant, it is important that
you use only DEX-COOLž(silicate-free) coolant.
If coolant other than DEX-COOLžis added to
the system, premature engine, heater core or
radiator corrosion may result. In addition, the engine
coolant will require change sooner Ð at 30,000 miles
(50,000 km) or 24 months, whichever occurs ®rst.
Damage caused by the use of coolant other
than DEX-COOL
žis not covered by your new vehicle
warranty.
5-23