coolant temperature CHEVROLET EXPRESS 2001 Owners Manual

2-23
Engine Coolant Heater (If Equipped)
In very cold weather, 0
F (-18
C) or colder, the engine
coolant heater can help. You'll get easier starting and
better fuel economy during engine warm
-up. Usually,
the coolant heater should be plugged in a minimum of
four hours prior to starting your vehicle. At temperatures
above 32
F (0
C), use of the coolant heater is
not required.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord.
The cord for the engine coolant heater is located on
the driver's side of the engine compartment and is
attached to the hose for the power steering reservoir.
3. Plug it into a normal, grounded 110
-volt AC outlet.
CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the wrong
kind of extension cord could overheat and cause
a fire. You could be seriously injured. Plug the
cord into a properly grounded three
-prong
11 0
-volt AC outlet. If the cord won't reach, use a
heavy
-duty three-prong extension cord rated for
at least 15 amps.
4. Before starting the engine, be sure to unplug
and store the cord as it was before to keep it away
from moving engine parts. If you don't, it could
be damaged.

2-24
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead of
trying to list everything here, we ask that you contact
your dealer in the area where you'll be parking your
vehicle. The dealer can give you the best advice for that
particular area.
Automatic Transmission Operation
There are several different positions for your shift lever.
Your vehicle is equipped with an automatic
transmission, and it features an electronic shift position
indicator within the instrument cluster. This display
must be powered anytime the shift lever is capable of
being moved out of the PARK (P) position. This means
that if your key is in OFF, but not locked, there will be
a small current drain on your battery which could
discharge your battery over a period of time.If you have a need to leave your key in the ignition in
OFF for an extended period for any reason, it is
recommended that you disconnect the battery cable from
the battery to prevent discharging your battery.
PARK (P): This position locks your rear wheels. It's the
best position to use when you start your engine because
your vehicle can't move easily.
CAUTION:
It is dangerous to get out of your vehicle if the
shift lever is not fully in PARK (P) with the
parking brake firmly set. Your vehicle can roll.
Don't leave your vehicle when the engine is
running unless you have to. If you have left the
engine running, the vehicle can move suddenly.
You or others could be injured. To be sure your
vehicle won't move, even when you're on fairly
level ground, always set your parking brake and
move the shift lever to PARK (P).
See ªShifting Into PARK (P)º in the Index.
If you're pulling a trailer, see ªTowing a Trailerº
in the Index.

2-60 Anti-Lock Brake System Warning Light
With the anti-lock brake
system, this light will
come on when you start
your engine and may stay
on for several seconds.
That's normal.
If the light stays on, or comes on when you're driving,
your vehicle needs service. If the regular brake system
warning light isn't on, you still have brakes, but you
don't have anti
-lock brakes. If the regular brake system
warning light is also on, you don't have anti
-lock brakes
and there's a problem with your regular brakes. See
ªBrake System Warning Lightº earlier in this section.
The anti
-lock brake system warning light should come
on briefly when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.
Engine Coolant Temperature Gage
This gage shows the
engine coolant temperature.
If the gage pointer moves
into the red area your
engine is too hot!
It means that your engine coolant has overheated.
If you have been operating your vehicle under normal
operating conditions, you should pull off the road, stop
your vehicle, and turn off the engine as soon as possible.
See ªEngine Overheatingº in the Index.

2-65 Malfunction Indicator Lamp (Service
Engine Soon Light) (Check Engine Light)
(8.1L Gasoline Engine -- Except California)
United States Canada
If this light comes on or flashes while you are driving,
two things may happen.
First, you won't notice any difference in engine
performance, but your tail pipe emissions may increase.
Second, your engine may not run properly or may stall
without warning. If either of these things happen, drive
or tow your vehicle to your dealer for service.This light should come on when the ignition is on, but
the engine is not running, as a check to show you it is
working. If it does not come on at all, have it repaired.
NOTICE:
If you keep driving your vehicle with this light
on, after a while, your emission controls may not
work as well, your fuel economy may not be as
good and your engine may not run as smoothly.
This could lead to costly repairs that may not be
covered by your warranty.
Reduced Engine Power
The REDUCED ENGINE
POWER light will come
on when the cooling system
temperature gets too hot
and the engine further
enters the engine coolant
protection mode.
See ªEngine Overheatingº in the Index for
further information.

2-67 Security Light
This light will come on
briefly when you turn the
ignition key to START.
The light will stay on until the engine starts. If the light
flashes, the Passlock

System has entered a tamper
mode. If the vehicle fails to start, see ªPasslockº in
the Index.
If the light comes on continuously while driving and
stays on, there may be a problem with the Passlock
System. Your vehicle will not be protected by Passlock,
and you should see your GM dealer.
Daytime Running Lamps Indicator Light
You have this light on the
instrument panel. It will
light whenever the DRL
are on. It is also a reminder
to turn on your headlamps
when driving at night.
Check Gages Light
The CHECK GAGES light
will come on briefly when
you are starting the engine.
If the light comes on and stays on while you are driving,
check your coolant temperature and engine oil pressure
gages to see if they are in the warning zones.

3-7
Air Conditioning
Before using your vehicle's air conditioning, open the
windows to clear the vehicle of hot air. This reduces the
time it takes for your vehicle to cool down. Then keep
your windows closed for the air conditioner to work at
its best.
You can use MAX A/C with the temperature knob in the
blue area when it's really hot outside and you need to
cool the inside air quickly. MAX A/C lets in only a little
air from the outside.
If you first use MAX A/C, you can then use A/C with
the temperature knob in the blue area, as soon as the
vehicle has cooled down, so outside air will be going
through your vehicle.
If your vehicle has rear air conditioning, setting it on
LO may enhance front A/C performance by allowing
trapped refrigerant in rear lines to circulate.
When the air conditioning, defrost or blend is on, you
may notice a slight increase or decrease in engine speed,
due to compressor operation. This is normal because the
system is designed to cycle the compressor on and off to
keep the desired temperature.
Heating
On cold days, use the floor setting with the temperature
knob in the red area. Outside air will be brought in
through the floor outlets. The heater works best if you
keep your windows closed while using it.
If you use the optional engine coolant heater before
starting your engine, your heating system will produce
warmer air faster to heat the passenger compartment in
cold weather. See ªEngine Coolant Heaterº in the Index.
Defrosting
Use defrost to remove fog or ice from the windshield
quickly in extremely cold conditions. The temperature
knob should be in the red area and the fan knob toward
high. The air conditioning compressor may operate in
this setting to dehumidify the air.

4-40 Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have extra
wiring and a heavy
-duty turn signal flasher (included in
the optional trailering package).
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.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If you turn
your engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do
get the overheat warning, see ªEngine Overheatingº in
the Index.

5-10
Engine Overheating
(Gasoline Engine)
You will find a coolant temperature gage on your
vehicle's instrument panel. If you have a diesel
engine, you will also find a low coolant light on your
instrument panel.
If your vehicle has a diesel engine, see ªEngine
Overheatingº in the Diesel Engine Supplement.
Overheated Engine Protection Operating
Mode (8.1L V8 Engine Only)
If an overheated engine condition exists and the
REDUCED ENGINE POWER light is displayed, an
overheat protection mode which alternates firing groups
of cylinders helps prevent engine damage. In this mode,
you will notice a loss in power and engine performance.
This operating mode allows your vehicle to be driven
to a safe place in an emergency. Driving extended
miles (km) and/or 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.
If Steam Is Coming From Your Engine

6-24
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.
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.
What to Use
Use a mixture of one-half clean, drinkable water and
one
-half DEX-COOL coolant which won't damage
aluminum parts. If you use this coolant mixture, you
don't need to add anything else.
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 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.

Short Trip/City Scheduled Maintenance
7-32
100,000 Miles (166 000 km)

Gasoline Engine Only: Inspect spark plug wires. An Emission Control Service.

Gasoline Engine Only: Replace spark plugs. An Emission Control Service.

Change automatic transmission fluid and filter if the vehicle has a diesel
engine, if the vehicle's GVWR is over 8600 lbs. or 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 you haven't used your vehicle under severe service conditions listed
previously and, therefore, haven't changed your automatic transmission fluid,
change both the fluid and filter.
Gasoline Engine Only (Except 8.1L V8): Inspect Positive Crankcase
Ventilation (PCV) valve. An Emission Control Service.
150,000 Miles (240 000 km)
Drain, flush and refill cooling system (or every 60 months since last service,
whichever occurs first). See ªEngine Coolantº in the Index for what to use.
Inspect hoses. Clean radiator, condenser, pressure cap and neck. Pressure test
cooling system and pressure cap. An Emission Control Service.
ACTUAL
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ACTUAL
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