2004 BUICK CENTURY heating

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

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.
Engine Overheating
The coolant temperature gage and the engine coolant
temperature warning light on the instrument panel
can indicate an overheated engine condition. See
Engine Coolant Temperature Gage on page 3-35and
Engine Coolant Temperature Warning Light on
page 3-35.
Overheated Engine Protection
Operating Mode
The emergency 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 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.
5-25

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.
CAUTION: (Continued)
CAUTION: (Continued)
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.
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.
5-26

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.
{CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Do not touch them. If
you do, you can be burned.
Do not run the engine if there is a leak. If you
run the engine, it could lose all coolant. That
could cause an engine re, and you could be
burned. Get any leak xed before you drive the
vehicle.If there seems to be no leak, with the engine on, check
to see if the electric engine cooling fans are running.
If the engine is overheating, both fans should be
running. If they are not the vehicle needs service.
Notice:Engine damage from running your engine
without coolant is not covered by your warranty. See
“Overheated Engine Protection Operating Mode”
in the Index for information on driving to a safe
place in an emergency.
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.
5-29

Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service,
see your GM Warranty booklet for details. For additional
information refer to the tire manufacturer’s booklet
included with your vehicle’s Owner’s Manual.{CAUTION:
Poorly maintained and improperly used tires
are dangerous.
Overloading your tires can cause
overheating as a result of too much
friction. You could have an air-out and a
serious accident. See “Loading Your
Vehicle” in the Index.
Underinated tires pose the same danger
as overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.
Overinated tires are more likely to be
cut, punctured or broken by a sudden
impact — such as when you hit a pothole.
Keep tires at the recommended pressure.
Worn, old tires can cause accidents. If
your tread is badly worn, or if your tires
have been damaged, replace them.
5-57

Circuit
BreakersUsage
TIRE RESET Tire Ination Monitor Reset Button
PWR/WNDW
PWR S/ROOFPower Windows, Power Sunroof
R/DEFOG Rear Window Defogger
PWR/ SEAT Power Seat
Blank Not Used
Fuses Usage
PRK/LCK Ignition Key Solenoid
Blank Not Used
Blank Not Used
PCM,
BCM, U/HIgnition Signal: Hot in Run and Start,
Powertrain Control Module, Body
Control Module, Underhood Relay
RADIO PREM.
SOUNDRemote Radio Premium Sound
PWR MIR Power Mirrors
Blank Not Used
INT/ILLUM Panel Dimming
Blank Not Used
IGN 0: CLSTR,
PCM & BCMIgnition Signal: Hot in Run, Unlock
and Start; Cluster, Powertrain
Control Module, Body Control
Module
Fuses Usage
Blank Not Used
Blank Not Used
Blank Not Used
ACCY
PWR BUSInterior Lamps
DR/ LCK Door Locks
Blank Not Used
R/LAMPS Taillamps, License Plate Lamps
Blank Not Used
CRUISE Cruise Control
Blank Not Used
CLSTR Instrument Panel Cluster
LTR Cigarette Lighter
STOP LAMPS Stoplamps
ONSTAR OnStar
®
PRK/LGHT Parking Lamps
Blank Not Used
CRNK SIG,
BCM, CLSTRCrank Signal, Body Control Module,
Cluster, Powertrain Control Module
HVACIgnition Signal, Heating, Ventilation,
and Air Conditioning Control Head
BTSI (REGAL) Not Used
AIR BAG Air Bag
BCM PWR Body Control Module
5-99

Fuses Usage
HAZRD Hazard Warning Flashers
LH HTD SEAT Not Used
Blank Not Used
BCM ACCYIgnition Signal: Hot in ACCESSORY
and RUN, Body Control Module
Blank Not Used
LOW BLWER Low Blower
ABS Anti-Lock Brakes
TRN SIG Turn Signals, Cornering Lamps
RADIO,
HVAC, RFA,
CLSTR ALDLRadio, Heating Ventilation and Air
Conditioning Head; Remote Keyless
Entry, Cluster
HI BLWR High Blower
RH HTD SEAT Not Used
STR/WHL
CNTRLAudio Steering Wheel Controls
WPR Windshield WipersUnderhood Fuse Block
Some fuses and relays are located in the underhood
fuse block on the passenger’s side of the vehicle in the
engine compartment. SeeEngine Compartment
Overview on page 5-12for more information on location.
5-100

Fuses Usage
1 Anti-Lock Brake System
2 Starter Solenoid
3 Power Seat, Rear Window Defogger
4High Blower, Hazard Flasher,
Stoplamps, Power Mirror,
Door Locks
5Ignition Switch, Stoplamps,
Anti-Lock Brake System, Turn
Signals, Cluster, Air Bag, Daytime
Running Lamps Module
6 Cooling Fan
7Retained Accessory Power, Remote
Keyless Entry, Data Link, Heating,
Ventilation, and Air Conditioning
Head; Cluster, Radio, Cigarette
Lighter
8Ignition Switch, Wipers, Autdio
Steering Wheel Controls, Body
Control Module, Power Windows,
Sunroof, Heating, Ventilation, and
Air Conditioning Controls; Daytime
Running Lamps, Rear Window
Defogger RelayRelays Usage
9 Cooling Fan 2
10 Cooling Fan 3
11 Starter Solenoid
12 Cooling Fan 1
13 Ignition Main
14 Air Pump (Optional)
15 Not Used
16 Horn
17 Fog Lamps
18 Not Used
19 Fuel Pump
5-101