engine oil BUICK CENTURY 2003 User Guide

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

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

What to Use
Use a mixture of one-halfclean, drinkable waterand
one-half DEX-COOLžcoolant which won't damage
aluminum parts. If you use this coolant mixture,
you don't need to add anything else.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can boil
before the proper coolant mixture will. Your
vehicle's coolant warning system is set for the
proper coolant mixture. With plain water or the
wrong mixture, your engine could get too hot
but you wouldn't get the overheat warning.
Your engine could catch ®re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
žcoolant.
Notice:If you use an improper coolant mixture,
your engine could overheat and be badly damaged.
The repair cost wouldn't be covered by your
warranty. Too much water in the mixture can freeze
and crack the engine, radiator, heater core and
other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
Notice:If you use the proper coolant, you don't
have to add extra inhibitors or additives which claim
to improve the system. These can be harmful.
Checking Coolant
The engine coolant recovery tank is located on the
passenger's side of the vehicle at the rear of the engine
compartment. See
Engine Compartment Overview on
page 5-12for more information on location.
5-24

Radiator Pressure Cap
Notice:Your radiator cap is a pressure-type cap
and must be tightly installed to prevent coolant loss
and possible engine damage from overheating.
Be sure the arrows on the cap line up with the
over¯ow tube on the radiator ®ller neck.
The radiator pressure cap is located near the front of
the engine compartment on the passenger's side of the
vehicle. See
Engine Compartment Overview on
page 5-12for more information on location.
Engine Overheating
You will ®nd a coolant temperature gage and a hot
engine warning light on your instrument panel.
See
Engine Coolant Temperature Gage on page 3-30andEngine Coolant Temperature Warning Light on
page 3-29.
Overheated Engine Protection
Operating Mode
The emergency engine protection operating mode
allows your vehicle to be driven to a safe place in an
emergency situation. If an overheated engine condition
exists, this protection mode alternates ®ring groups
of cylinders to help prevent engine damage. In
this mode, you will notice a signi®cant loss in power and
engine performance. The engine coolant temperature
gage indicator will move to the red area, showing that an
overheated engine condition exists. Driving extended
miles (km) and/or towing a trailer in the overheated
protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant loss, change the oil and reset the oil
life system. See ªEngine Oilº in the Index.
5-26

Cooling System
When you decide it's safe to lift the hood, here's what
you'll see:
A. Coolant Recovery Tank
B. Electric Engine Cooling Fan
C. Radiator Pressure Cap{CAUTION:
An electric engine cooling fan under the hood
can start up even when the engine is not
running and can injure you. Keep hands,
clothing and tools away from any underhood
electric fan.
If the coolant inside the coolant recovery tank is boiling,
don't do anything else until it cools down. The vehicle
should be parked on a level surface.
5-29