1999 CHEVROLET CORVETTE cooling

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CAUTION:
It can be dangerous to drive with the hatch/trunk
lid open because carbon monoxide (CO) gas can
come into your vehicle. You can't see or smell
CO. It can cause unconsciousness and even death.
If you must drive with the hatch/trunk lid open
or if electrical wiring or other cable connections
must pass through the seal between the body and
the hatch/trunk lid:

Make sure all other windows are shut.

Turn the fan on your heating or cooling
system to its highest speed with the setting
on BI
-LEVEL or VENT. That will force
outside air into your vehicle. See ªComfort
Controlsº in the Index.

If you have air outlets on or under the
instrument panel, open them all the way.
See ªEngine Exhaustº in the Index.
NOTICE:
If you put things in the hatch/trunk area, be sure
they won't break the glass when you close it.
Never slam the hatch/trunk lid down. You could
break the glass or damage the defogger grid.
When you close the hatch/trunk lid, make sure
you pull down from the center, not the sides. If
you pull the hatch/trunk lid down from the side
too often, the weatherstrip can be damaged.
NOTICE:
Do not store heavy or sharp objects in the rear
storage compartments located in the hatch/trunk
area. If you do, the objects could damage
the underbody.

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Comfort Controls
This section tells you how to make your air system work
for you. Your comfort control system uses
ozone
-friendly R-134a refrigerant.
With these systems, you can control the heating, cooling
and ventilation in your vehicle. Your vehicle also has a
flow
-through ventilation system described later in
this section.
Manual Comfort Controls
Fan Knob
The left knob is the fan knob and controls the force of
air you want. Turn the knob clockwise to increase fan
speed or counterclockwise to decrease fan speed. The
fan must be turned on for the air conditioning
compressor to operate.
Temperature Knob
The center knob controls the temperature of the air
coming through the system. Turn it counterclockwise
(toward the blue area) for cooler air. Turn it clockwise
(toward the red area) for warmer air.
Mode Knob
The right knob selects the direction of where the air will
enter the vehicle.
UPPER: This setting directs most of the air through
the instrument panel outlets with a very small amount of
air directed to the lower outlets.
BI-LEVEL: This setting directs air into the
vehicle in two ways. Cooler air is directed toward your
upper body through the instrument panel outlets, while
warmer air is directed through the lower outlets.

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When adjusting the temperature, start with a driver-set
temperature of 73
F (23
C) until you determine your
comfort zone. If you choose 60
F (16
C), the
system will remain at maximum cooling and will not
automatically adjust fan speed or air delivery. If you
choose 90
F (32
C), the system will remain at
maximum heating and will not automatically adjust fan
speed or air delivery. Choosing either maximum setting
will not cause the system to heat or cool any faster.
Turning the knob past either maximum setting has no
effect on the operation of the system.
Passenger Temperature Offset
The PASSENGER knob changes the temperature on the
passenger's side of the vehicle. When the knob is in the
12 o'clock position, the passenger's temperature is the
same as the driver's. Turn the knob clockwise for
warmer air on the passenger's side, counterclockwise for
cooler air. If the driver
-set temperature is set at 60
F
(16
C) or 90
F (32
C), turning the passenger knob
has no effect because the system is locked at a
maximum setting.Automatic Operation
Press the AUTO button to place the entire system in the
automatic mode. After a five
-second display of the
current settings, only the word AUTO and the outside
temperature will be shown on the digital display. The
system will operate to achieve your comfort set
temperature as quickly as possible. If you have set the
driver temperature at 60
F (16
C) or 90
F (32
C),
the system will not operate automatically until a
different temperature is selected. The AUTO control
system works best with the windows up and the
removable roof installed or the convertible top up.
A Typical Cold Weather Example:
Your vehicle has been parked outside overnight in cold
weather (below 32
F/ 0
C) and you have set the driver
temperature at 73
F (23
C) and have selected the
AUTO mode. The system will automatically adjust the
temperature output to maximum heating. The fan will
start at a low speed. This is to avoid blowing cold air
into the vehicle. The length of the delay depends on the
amount of time since the engine was last started, the
outside temperature and the engine coolant temperature.
As the coolant warms up, the fan speed will gradually
increase. Air will flow to the floor with some air to
the windshield to prevent fogging under most
normal conditions.

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As the interior of the vehicle warms up to your comfort
set temperature, the fan speed will decrease and the
temperature output may become cooler. If the interior
temperature continues to warm up due to heating
from the sun or outside temperature increases, the
system may switch to other air delivery modes
(typically DEFOG or BI
-LEVEL).
A Typical Hot Weather Example:
The vehicle has been parked outside all day in hot
weather (above 70
F/ 21
C) and you have set the driver
temperature at 73
F (23
C) and have selected the
AUTO mode. The system will automatically adjust the
temperature output to maximum cooling. The blower
will start at a low speed momentarily to push the hot air
to the floor of the vehicle and then go to a higher blower
speed with cold airflow out of the instrument panel
outlets. A small amount of airflow will continue through
the lower ducts to cool the floor area.The air intake may start in the recirculated mode for
maximum cooling performance. As the interior of the
vehicle cools down to your comfort set temperature, the
fan speed will decrease and the temperature output may
become warmer. The air intake may shift from
recirculation to fresh air mode. If the interior continues
to cool due to a decrease in the amount of heat the
vehicle is absorbing from the sun or a decrease in the
outside temperature, the system could switch to other air
delivery modes (typically BI
-LEVEL or DEFOG).
Manual Settings
With the Automatic Electronic Dual Climate Control
System, there are several manual settings you can use to
control the system and override the AUTO operation.
You can program the fan speed, air delivery mode, air
intake mode and control the air conditioning operation
using these settings. The system will still determine the
temperature output level based on the driver
-set
temperature and the passenger temperature offset.

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Outside Air Temperature Sensor
This sensor is located in the air intake under the front
bumper of the vehicle. Information from this sensor
is used for the outside air temperature readings shown
on the digital display for the automatic climate
control system.
If the outside temperature goes up, the displayed
temperature will not change until:

The vehicle's speed is above 20 mph (32 km/h) for
one and a half minutes.

The vehicle's speed is above 45 mph (72 km/h) for
one minute.
These delays help prevent false readings. If the
temperature goes down, the outside temperature display
is updated immediately.
If the vehicle has been turned off for more than three
hours, the current outside temperature will be shown
when you start the vehicle. If it has been turned off for
less than three hours, the temperature will be recalled
from the previous vehicle operation.Inside Temperature Sensor
This sensor is located to the left of the ignition switch.
The automatic climate control system uses this sensor to
receive information, so if you block or cover it, the
system will not function properly.
Air Conditioning
On very hot days, the vehicle will cool down more
quickly and economically if you open the windows long
enough to let hot inside air escape. Then keep the
windows closed in order to allow the air conditioning to
work best. Maximum cooling will occur when the
recirculate setting is operating, airflow direction is in the
upper mode, and the temperature control knob
(on a manual climate control system) is turned all the
way to the blue area. These settings will be selected
by the Automatic Electronic Dual Climate Control
System if operating in AUTO when maximum cooling
is required.
When the air conditioning is on, you may sometimes
notice slight changes in the vehicle's engine
performance and power. This is normal. The system is
designed to help fuel economy while maintaining the
desired cooling level.

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If you drive regularly in steep country, or if you're
planning to visit there, here are some tips that can make
your trips safer and more enjoyable.

Keep your vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system and
transmission. These parts can work hard on
mountain roads.

Know how to go down hills. The most important
thing to know is this: let your engine do some of the
slowing down. Shift to a lower gear when you go
down a steep or long hill.
CAUTION:
If you don't shift down, your brakes could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a
hill. You could crash. Shift down to let your
engine assist your brakes on a steep
downhill slope.
CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have to
do all the work of slowing down. They could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a hill.
You could crash. Always have your engine running
and your vehicle in gear when you go downhill.

Know how to go uphill. You may want to shift down
to a lower gear. The lower gears help cool your engine
and transmission, and you can climb the hill better.

Stay in your own lane when driving on two
-lane
roads in hills or mountains. Don't swing wide or cut
across the center of the road. Drive at speeds that let
you stay in your own lane.

As you go over the top of a hill, be alert. There could be
something in your lane, like a stalled car or an accident.

You may see highway signs on mountains that warn of
special problems. Examples are long grades, passing or
no
-passing zones, a falling rocks area or winding
roads. Be alert to these and take appropriate action.

5-
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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
-3 Other Warning Devices
5
-3 Jump Starting
5
-8 Towing Your Vehicle5
-8 Engine Overheating
5
-11 Cooling System
5
-18 If a Tire Goes Flat
5
-18 If You're Stuck: In Sand, Mud, Ice or Snow

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Cooling System
When you decide it's safe to lift the hood, here's what
you'll see:
A. Electric Engine Cooling Fans
B. Coolant Surge Tank
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 surge tank is boiling,
don't do anything else until it cools down.