1999 PONTIAC BONNEVILLE radiator

First Edition for Pontiac Bonneville Owner's Manual ± 1999
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3-4
Mode Button
Press this button to deliver air through the floor, middle
or windshield outlets. The system will stay in the
selected mode until the MODE or AUTO button is
pushed. Press the up arrow to cycle through the
available modes.
Automatic Operation
When the system is set for AUTO, sensors will control
the air delivery mode. Air will come from the floor,
middle and windshield outlets. The fan speed will vary
as the system maintains the selected temperature setting.
To find your comfort zone, start with 75
F (24
C)
temperature setting and allow about 20 minutes for the
system to regulate. Press the TEMP button up or down to
adjust the temperature setting if necessary. If you choose
the temperature setting of 60
F (15
C), the system will
remain at that maximum cooling setting and will not
regulate the fan speed. If you choose the temperature
setting of 90
F (33
C), the system will remain at that
maximum heating setting and will not regulate the fan
speed. Choosing either maximum setting will not cause the
system to heat or cool any faster.Pressing the AUTO button will display the requested
temperature, fan speed and air delivery mode for
five seconds, then change to display the outside air
temperature. Be careful not to put anything over the
sensor located in the middle of the instrument panel near
the windshield, or over the sensor in the grille above the
radio. These sensors are used by the automatic system to
regulate temperature.
The exterior temperature display sensor is in front of the
vehicle, near the radiator. The displayed temperature is
most accurate when the vehicle is moving. During stops,
or while idling, the display shows the previous driving
temperature for best system control.
To avoid blowing cold air in cold weather, the system
will delay turning on the fan until warm air is available.
The length of delay depends on outside air temperature,
engine coolant temperature, and time since the engine
was last started. Pushing the fan button will override this
delay and change the fan to a selected single speed.
If you leave your vehicle, the system will remember the
control setting the next time you start your engine.

First Edition for Pontiac Bonneville Owner's Manual ± 1999
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5-12
Cooling System
When you decide it's safe to lift the hood, here's what
you'll see:
H±45±0741±T
A. Coolant Recovery Tank
B. Radiator Pressure Cap
C. Electric Engine Cooling Fans
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.
H±45±0742±T

First Edition for Pontiac Bonneville Owner's Manual ± 1999
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5-13
The coolant level should be at or above the FULL
COLD mark. If it isn't, you may have a leak 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. Don't touch them. If you
do, you can be burned.
Don't run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
NOTICE:
Engine damage from running your engine
without coolant isn't covered by your warranty.
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.

First Edition for Pontiac Bonneville Owner's Manual ± 1999
yellowblue
5-14 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 FULL 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.
NOTICE:
In cold weather, water can freeze and crack the
engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.

First Edition for Pontiac Bonneville Owner's Manual ± 1999
yellowblue
5-15
H±45±0326±T
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. Don't spill coolant on a hot engine.
When the coolant in the coolant recovery tank is at the
FULL COLD mark, start your vehicle.
If the overheat warning continues, there's one more
thing you can try. You can add the proper coolant
mixture directly to the radiator, but be sure the cooling
system is cool before you do it.

First Edition for Pontiac Bonneville Owner's Manual ± 1999
yellowblue
5-16
CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the radiator
pressure cap
-- even a little -- they can come out
at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap, is hot. Wait for the cooling system and
radiator pressure cap to cool if you ever have to
turn the pressure cap.
W±35±1020±S

First Edition for Pontiac Bonneville Owner's Manual ± 1999
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5-17 How to Add Coolant to the Radiator
C±45±6704±T
1. You can remove the radiator pressure cap when the
cooling system, including the radiator pressure cap
and upper radiator hose, is no longer hot. Turn the
pressure cap slowly counterclockwise until it first
stops. (Don't press down while turning the
pressure cap.)
If you hear a hiss, wait for that to stop. A hiss means
there is still some pressure left.
C±45±6705±T
2. Then keep turning the pressure cap, but now push
down as you turn it. Remove the pressure cap.

First Edition for Pontiac Bonneville Owner's Manual ± 1999
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5-18
C±45±6703±T
3. Fill the radiator with the proper DEX-COOL

coolant mixture, up to the base of the filler neck.
(See ªEngine Coolantº in the Index for more
information about the proper coolant mixture.)
H±45±0326±T
4. Then fill the coolant recovery tank to the
FULL COLD mark.
5. Put the cap back on the coolant recovery tank, but
leave the radiator pressure cap off.