engine overheat GMC ENVOY 1999 Owners Manual

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The 1999 GMC Envoy Owner's Manual
1-1 Seats and Restraint SystemsThis section tells you how to use your seats and safety belts properly. It also explains the air bag system.
2-1 Features and ControlsThis section explains how to start and operate your vehicle.
3-1 Comfort Controls and Audio SystemsThis section tells you how to adjust the ventilation and comfort controls and how to operate your audio system.
4-1 Your Driving and the RoadHere you'll find helpful information and tips about the road and how to drive under different conditions.
5-1 Problems on the RoadThis section tells you what to do if you have a problem while driving, such as a flat tire or overheated engine, etc.
6-1 Service and Appearance CareHere the manual tells you how to keep your vehicle running properly and looking good.
7-1 Maintenance ScheduleThis section tells you when to perform vehicle maintenance and what fluids and lubricants to use.
8-1 Customer Assistance InformationThis section tells you how to contact GMC for assistance and how to get service and owner publications.
It also gives you information on ªReporting Safety Defectsº on page 8-10.
9-1 IndexHere's an alphabetical listing of almost every subject in this manual. You can use it to quickly find
something you want to read.
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NOTICE:
Your engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way
the engine operates. Before adding electrical
equipment, check with your dealer. If you don't,
your engine might not perform properly.
If you ever have to have your vehicle towed, see
the part of this manual that tells how to do it
without damaging your vehicle. See ªTowing
Your Vehicleº in the Index.
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.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located on the driver's side of the engine
compartment, behind the underhood fuse block.
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.
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Pull the BRAKE RELEASE lever fully. It is located on
the bottom of the driver's side of the instrument panel.
NOTICE:
Driving with the parking brake on can cause
your rear brakes to overheat. You may have to
replace them, and you could also damage other
parts of your vehicle.
If you are towing a trailer and you must park on a hill,
see ªTowing a Trailerº in the Index. That section shows
what to do first to keep the trailer from moving.
Shifting Into PARK (P)
CAUTION:
It can be 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. 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, use the steps that
follow. Always put the shift lever fully in
PARK (P) with the parking brake firmly set. If
you're pulling a trailer, see ªTowing a Trailerº in
the Index.
1. Hold the brake pedal down with your right foot and
set the parking brake.
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2-27
2. Move the shift lever into PARK (P) position
like this:

Hold in the button on the front of the lever.

Push the lever all the way toward the front of
the vehicle.
3. Turn the ignition key to LOCK.
4. Remove the key and take it with you. If you can
leave your vehicle with the key, your vehicle is in
PARK (P).
Leaving Your Vehicle With the
Engine Running
CAUTION:
It can be dangerous to leave your vehicle with the
engine running. Your vehicle could move
suddenly if the shift lever is not fully in PARK (P)
with the parking brake firmly set. And, if you
leave the vehicle with the engine running, it could
overheat and even catch fire. You or others could
be injured. Don't leave your vehicle with the
engine running unless you have to.
If you have to leave your vehicle with the engine
running, be sure your vehicle is in PARK (P) and your
parking brake is firmly set before you leave it. After
you've moved the shift lever into PARK (P), hold the
regular brake pedal down. Then, see if you can move the
shift lever away from PARK (P) without pressing the
button on the shift lever. If you can, it means that the
shift lever wasn't fully locked into PARK (P).
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2-70 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 driving
conditions, you should pull off the road, stop your
vehicle and turn off the engine as soon as possible.
The ªProblems on the Roadº section of this manual
shows you what to do. See ªEngine Overheatingº in
the Index.
Malfunction Indicator Lamp
(Service Engine Soon Light)
United States Canada
Your vehicle is equipped with a computer which
monitors operation of the fuel, ignition and emission
control systems.
This system is called OBD II (On
-Board
Diagnostics
-Second Generation) and is intended to
assure that emissions are at acceptable levels for the life
of the vehicle, helping to produce a cleaner
environment. The SERVICE ENGINE SOON light
comes on to indicate that there is a problem and service
is required. Malfunctions often will be indicated by the
system before any problem is apparent. This may
prevent more serious damage to your vehicle. This
system is also designed to assist your service technician
in correctly diagnosing any malfunction.
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CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the transmission
is in PARK (P). This is because the NEUTRAL
position on the transfer case overrides the
transmission. You or someone else could be
injured. If you are going to leave your vehicle, set
the parking brake and shift the transmission to
PARK (P). But do not shift the transfer case to
the NEUTRAL position. Leave the transfer case
in a drive gear.
Driving Downhill
When off-roading takes you downhill, you'll want to
consider a number of things:

How steep is the downhill? Will I be able to maintain
vehicle control?

What's the surface like? Smooth? Rough? Slippery?
Hard
-packed dirt? Gravel?

Are there hidden surface obstacles? Ruts?
Logs? Boulders?
What's at the bottom of the hill? Is there a hidden
creek bank or even a river bottom with large rocks?
If you decide you can go down a hill safely, then try to
keep your vehicle headed straight down, and use a low
gear. This way, engine drag can help your brakes and
they won't have to do all the work. Descend slowly,
keeping your vehicle under control at all times.
CAUTION:
Heavy braking when going down a hill can cause
your brakes to overheat and fade. This could
cause loss of control and a serious accident.
Apply the brakes lightly when descending a hill
and use a low gear to keep vehicle speed
under control.
Q:Are there some things I should not do when
driving down a hill?
A:Yes! These are important because if you ignore
them you could lose control and have a
serious accident.
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When driving downhill, avoid turns that take you
across the incline of the hill. A hill that's not too
steep to drive down may be too steep to drive across.
You could roll over if you don't drive straight down.

Never go downhill with the transmission in
NEUTRAL (N). This is called ªfree
-wheeling.º Your
brakes will have to do all the work and could
overheat and fade.
Q:Am I likely to stall when going downhill?
A:It's much more likely to happen going uphill. But if
it happens going downhill, here's what to do.

Stop your vehicle by applying the regular brakes.
Apply the parking brake.

Shift to PARK (P) and, while still braking, restart
the engine.

Shift back to a low gear, release the parking brake,
and drive straight down.

If the engine won't start, get out and get help.
Driving Across an Incline
Sooner or later, an off-road trail will probably go across
the incline of a hill. If this happens, you have to decidewhether to try to drive across the incline. Here are some
things to consider:

A hill that can be driven straight up or down may be
too steep to drive across. When you go straight up or
down a hill, the length of the wheel base (the distance
from the front wheels to the rear wheels) reduces the
likelihood the vehicle will tumble end over end. But
when you drive across an incline, the much more
narrow track width (the distance between the left and
right wheels) may not prevent the vehicle from tilting
and rolling over. Also, driving across an incline puts
more weight on the downhill wheels. This could cause
a downhill slide or a rollover.

Surface conditions can be a problem when you drive
across a hill. Loose gravel, muddy spots, or even wet
grass can cause your tires to slip sideways, downhill.
If the vehicle slips sideways, it can hit something
that will trip it (a rock, a rut, etc.) and roll over.

Hidden obstacles can make the steepness of the
incline even worse. If you drive across a rock with
the uphill wheels, or if the downhill wheels drop into
a rut or depression, your vehicle can tilt even more.
For reasons like these, you need to decide carefully
whether to try to drive across an incline. Just because the
trail goes across the incline doesn't mean you have to
drive it. The last vehicle to try it might have rolled over.
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4-52 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.
You should use THIRD (3) when towing a trailer.
Operating your vehicle in THIRD (3) when towing a
trailer will minimize heat buildup and extend the life of
your transmission.
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.
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. Then turn your wheels into the curb if
facing downhill or into traffic if facing uphill.
2. Have someone place chocks under the trailer 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 then shift into PARK (P).
5. Release the regular brakes.
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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
-2 Other Warning Devices
5
-3 Jump Starting
5
-7 Towing Your Vehicle
5
-8 Engine Overheating5
-18 Engine Fan Noise
5
-18 If a Tire Goes Flat
5
-19 Changing a Flat Tire
5
-30 If You're Stuck: In Sand, Mud, Ice or Snow
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5-8
Engine Overheating
You will find a coolant temperature gage on your
vehicle's instrument panel. See ªGagesº in the Index.
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. 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 fire. You or
others could be badly burned. Stop your engine if
it overheats, and get out of the vehicle until the
engine is cool.
NOTICE:
If your engine catches fire because you keep
driving with no coolant, your vehicle can be
badly damaged. The costly repairs would not be
covered by your warranty.
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