1999 BUICK CENTURY heating

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3-9
RECIRC: This setting recirculates much of the air
inside your vehicle. This setting is not permitted in
FRONT defrost mode and is only permitted in
WINDSHIELD/FLOOR mode if the compressor is
turned on. The indicator light will be lit when
recirculation is engaged, but will light for one second
and then turn off if selected when not permitted.
Heating (Engine Coolant Heater)
If your vehicle has an engine coolant heater, you can use
it to help your system provide warm air faster when it's
cold outside
-- 0
F (-18
C) or lower. An engine
coolant heater warms the coolant your engine and
heating system use to provide heat. See ªEngine Coolant
Heaterº in the Index.
Defogging and Defrosting
Your system has two settings for clearing the front and
side windows. To defrost the windows quickly, press the
FRONT button; set the temperature to 90
F (32
C),
select high fan speed and turn the DUAL button off. To
warm passengers while keeping the windows clear, push
the AIR FLOW button until WINDSHIELD/FLOOR
appears in the display. Select fan speed for comfort and
windshield clearing performance.
Rear Window Defogger
The rear window defogger uses a warming grid to
remove fog from the rear window. Press the button to
turn the rear defogger on. It will turn itself off after
about 10 minutes. If you turn it on again, the rear
defogger will only run for about five minutes before
turning off. You can also turn it off by pressing the
button again. The picture above on the left refers to the
defogger button that is found on a Manual Single Zone
Climate Control system or Dual ComforTemp Climate
Control system; the button on the right is found on the
Dual Automatic ComforTemp Climate Control system.

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If you choose to add a cellular telephone to your vehicle,
and the antenna needs to be attached to the glass, be sure
that you do not damage the grid lines for the AM
-FM
antenna. There is enough space between the lines to
attach a cellular telephone antenna without interfering
with radio reception.
On cars equipped with the rear window defogger and built
-in
antenna, the defogger grid serves as a radio antenna. If you
have this feature on your car, do not apply aftermarket glass
tinting to the back glass. The metallic film in some tinting
materials will interfere with or distort the incoming radio
reception. Care must be taken when cleaning the rear
window because breaks in the resistive material heating
element will adversely affect radio performance and
defogger performance. See your dealer for details.
Diversity Antenna System (If Equipped)
Your AM-FM antennas are located in the front
windshield and rear window. Be sure that the inside
surfaces of the front windshield and rear window are not
scratched and that the lines on the glass are not
damaged. If the inside surfaces are damaged, they could
interfere with radio reception. Also, for proper radio
reception, the antenna connector at the top
-center of the
front windshield and the antenna connector at the
top
-center of the rear window need to be properly
attached to the posts on the glass.
NOTICE:
Do not try to clear frost or other material from
the inside of the rear window with a razor blade
or anything else that is sharp. This may damage
the rear defogger grid and affect your radio's
ability to pick up stations clearly. The repairs
wouldn't be covered by your warranty.
If, when you turn on your rear window defogger, you
hear static on your radio station, it could mean that a
defogger grid line has been damaged. If this is true, the
grid line must be repaired.
If you choose to add an aftermarket cellular telephone to
your vehicle, and the antenna needs to be attached to the
glass, be sure that you do not damage the grid lines for
the AM
-FM antennas or place the cellular telephone
antenna over the grid lines.

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4-37 Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle may need a different
turn signal flasher and/or extra wiring. Check with your
dealer. The arrows on your instrument panel will flash
whenever you signal a turn or lane change. Properly
hooked up, the trailer lamps will also flash, telling other
drivers you're about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will flash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind you
are seeing your signal when they are not. It's important
to check occasionally to be sure the trailer bulbs are
still working.
Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If you don't shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
On a long uphill grade, shift down and reduce your
speed to around 45 mph (70 km/h) to reduce the
possibility of engine and transaxle overheating.
If you are towing a trailer, you may want to drive in
DRIVE (D) instead of AUTOMATIC OVERDRIVE (
)
(or, as you need to, a lower gear).
Parking on Hills
CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People can
be injured, and both your vehicle and the trailer
can be damaged.
But if you ever have to park your rig on a hill, here's
how to do it:
1. Apply your regular brakes, but don't shift into
PARK (P) yet.
2. Have someone place chocks under the
trailer's wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your parking
brake, and shift to PARK (P).
5. Release the regular brakes.

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4-38 When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:

Start your engine;

Shift into a gear; and

Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transaxle fluid (don't overfill),
engine oil, drive belt, cooling system and brake system.
Each of these is covered in this manual, and the Index
will help you find them quickly. If you're trailering, it's
a good idea to review this information before you start
your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Engine Cooling When Trailer Towing
Your cooling system may temporarily overheat during
severe operating conditions. See ªEngine Overheatingº
in the Index.

5-
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5-1
Section 5 Problems on the Road
Here you'll find what to do about some problems that can occur on the road.
5
-2 Hazard Warning Flashers
5
-2 Other Warning Devices
5
-3 Jump Starting
5
-8 Towing Your Vehicle
5
-9 Engine Overheating5
-12 Cooling System
5
-20 If a Tire Goes Flat
5
-21 Changing a Flat Tire
5
-32 Compact Spare Tire
5
-33 If You're Stuck: In Sand, Mud, Ice or Snow

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Engine Overheating
You will find a coolant temperature gage and a hot
engine warning light on your instrument panel. See
ªEngine Coolant Temperature Gageº and ªEngine
Coolant Temperature Warning Lightº in the Index. You
also have a LOW COOLANT warning light on your
instrument panel. See ªLow Coolant Warning Lightº in
the Index.
Overheated Engine Protection
Operating Mode
This emergency operating mode allows your vehicle to
be driven to a safe place in an emergency situation.
Should an overheated engine condition exist, an
overheat protection mode which alternates firing groups
of three cylinders helps prevent engine damage. In this
mode, you will notice a significant loss in power and
engine performance. The low coolant light may come on
and the temperature gage will indicate an overheat
condition exists. Towing a trailer in the overheat
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 and change the oil.
See ªEngine Oilº in the Index.

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NOTICE:
When adding coolant, it is important that you use
only DEX
-COOL
(silicate-free) coolant.
If coolant other than DEX-COOL is added to the
system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
-- at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the use
of coolant other than DEX
-COOL
is not
covered by your new vehicle warranty.
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 aren't, your vehicle needs service.
How to Add Coolant to the Coolant
Recovery Tank
If you haven't found a problem yet, but the coolant level
isn't at the COLD mark, add a 50/50 mixture of clean,
drinkable water and DEX
-COOL
engine coolant at the
coolant recovery tank. (See ªEngine Coolantº in the
Index for more information.)
CAUTION:
Adding only plain water to your cooling system
can be dangerous. Plain water, or some other
liquid like 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 fire and you or others could be burned. Use
a 50/50 mixture of clean, drinkable water and
DEX
-COOL
coolant.

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Radiator Pressure Cap
NOTICE:
Your radiator cap is a 15 psi (105 kPa)
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 overflow tube on the radiator
filler neck.
When you replace your radiator pressure cap, an
ACDelco
cap is recommended.
Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant system. The thermostat stops the
flow of coolant through the radiator until the coolant
reaches a preset temperature.
When you replace your thermostat, an ACDelco


thermostat is recommended.
Engine Coolant
The cooling system in your vehicle is filled with
DEX
-COOL
engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX
-COOL
extended 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 ªEngine Overheatingº in the Index.
A 50/50 mixture of clean, drinkable water and
DEX
-COOL
coolant will:

Give freezing protection down to
-34F (-37C).

Give boiling protection up to 265F (129C).

Protect against rust and corrosion.

Help keep the proper engine temperature.

Let the warning lights and gages work as
they should.