2005 BUICK CENTURY engine

{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 backres.
If it is not there and the engine backres,
you could be burned. Do not 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 backre
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 are driving.
Automatic Transaxle Fluid
When to Check and Change
A good time to check the 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 90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or
delivery service.
If the vehicle is not used under any of these conditions,
change the uid and lter at 100,000 miles (166 000 km).
SeeScheduled Maintenance 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 the
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 the transaxle uid.
Wait at least 30 minutes before checking the transaxle
uid level if you have been driving:
When outside temperatures are above 90°F (32°C).
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 180°F to 200°F
(82°C to 93°C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50°F
(10°C). If it is colder than 50°F (10°C), you may have to
drive longer.
Checking the Fluid Level
Prepare the vehicle as follows:
Park the 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. SeeEngine
Compartment Overview
on page 5-12for more
information on location.
5-20

Engine Coolant
The cooling system in the vehicle is lled with
DEX-COOL®engine coolant. This coolant is designed
to remain in the vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs rst, if only
DEX-COOL
®extended life coolant is added.
The following explains the cooling system and how to
add coolant when it is low. If there is a problem
with engine overheating or if coolant needs to be added
to the radiator, seeEngine Overheating on page 5-25.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
Give freezing protection down to−34°F (−37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Let the warning lights and gages work as
they should.
Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your vehicle.
What to Use
Use a mixture of one-half clean, drinkable water and
one-half DEX-COOL®coolant which will not damage
aluminum parts. If this coolant mixture is used, nothing
else needs to be added.
{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 would not 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
®coolant.
5-22

Notice:If you use an improper coolant mixture,
your engine could overheat and be badly damaged.
The repair cost would not be covered by your
warranty. Too much water in the mixture can freeze
and crack the engine, radiator, heater core and
other parts.
If coolant has to be added more than four times a year,
have your dealer check the cooling system.
Notice:If you use the proper coolant, you do not
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. SeeEngine Compartment Overview on
page 5-12for more information on location.
The vehicle must be
on a level surface.
When the engine is cold,
the coolant level should be
at the COLD mark or a
little higher.
When the engine is warm, the level should be up to the
HOT mark or a little higher.
5-23

Adding Coolant
If more coolant is needed, add the proper DEX-COOL®
coolant mixture at the coolant recovery tank, but be
careful not to spill it.
If the coolant recovery tank is completely empty, add
coolant to the radiator. See “How to Add Coolant to the
Radiator” later in this section.
{CAUTION:
Turning the radiator pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. With the coolant recovery tank, you will
almost never have to add coolant at the
radiator. Never turn the radiator pressure
cap — even a little — when the engine and
radiator are hot.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol,
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
Occasionally check the coolant level in the radiator.
For information on how to add coolant to the radiator,
seeCooling System on page 5-27.
Radiator Pressure Cap
Notice:The radiator cap on your vehicle 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 overow 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. SeeEngine Compartment Overview on
page 5-12for more information on location.
5-24

Engine Overheating
The coolant temperature gage and the engine coolant
temperature warning light on the instrument panel
can indicate an overheated engine condition.
SeeEngine Coolant Temperature Gage on page 3-35
andEngine Coolant Temperature Warning Light on
page 3-35.
If Steam Is Coming From Your Engine
{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood.
Stay away from the engine if you see or hear
steam coming from it. Just turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
CAUTION: (Continued)
CAUTION: (Continued)
If you keep driving when your engine is
overheated, the liquids in it can catch re.
You or others could be badly burned. Stop
your engine if it overheats, and get out of the
vehicle until the engine is cool.
See “Overheated Engine Protection Operating
Mode” underEngine Overheating on page 5-25
for information on driving to a safe place in
an emergency.
Notice:If your engine catches re because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would not
be covered by your warranty. See “Overheated
Engine Protection Operating Mode” underEngine
Overheating on page 5-25for information on driving
to a safe place in an emergency.
5-25

If No Steam Is Coming From
Your Engine
An overheated engine warning can indicate a
serious problem.
If there is an overheated engine warning and you do not
see or hear any steam, the problem may not be too
serious. Sometimes the engine can get a little too hot
when the vehicle:
Climbs a long hill on a hot day.
Stops after high-speed driving.
Idles for long periods in traffic.
Tows a trailer.
If an overheated engine warning appears with no sign of
steam, try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL (N)
while stopped. If it is safe to do so, pull off the road,
shift to PARK (P) or NEUTRAL (N) and let the
engine idle.
2. Adjust the heater to the highest temperature and fan
speed settings and open the window as necessary.
If the overheated engine warnings no longer exist,
you can drive. Just to be safe, drive slower for about
10 minutes. If the warnings do not come back on,
you can drive normally.
If the warning continues, and you have not stopped,
pull over, stop, and park the vehicle right away.If there is still no sign of steam, idle the engine for
three minutes while you are parked. If the warning still
exists,turn off the engine and get everyone out of
the vehicleuntil it cools down. Also, see “Overheated
Engine Protection Operating Mode” later in this section.
You may decide not to lift the hood but to get service
help right away.
Overheated Engine Protection
Operating Mode
The overheated engine protection operating mode allows
the 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, there will be
a signicant loss in power and engine performance.
The engine coolant temperature gage indicator will move
to the red area, and the engine coolant temperature
warning light will come on, showing that an overheated
engine condition exists. Driving extended miles (km)
and/or towing a trailer in the overheated engine 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. SeeEngine Oil on page 5-13.
5-26

Cooling System
When it is safe to lift the hood, this is what you will see:
A. Coolant Recovery Tank
B. Electric Engine Cooling Fans
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,
do not do anything else until it cools down. The vehicle
should be parked on a level surface.
When the engine is cold, the coolant level should be at
or above the COLD mark on the coolant recovery
tank. If it is not, there may be a leak at the pressure cap
or in the radiator hoses, heater hoses, radiator, water
pump, or somewhere else in the cooling system.
5-27