tires GMC ENVOY 2002 Owner's Guide

4-54 Total Weight on Your Vehicle's Tires
Be sure your vehicle's tires are inflated to the upper
limit for cold tires. You'll find these numbers on the
Certification label at the rear edge of the driver's door or
see ªTire Loadingº in the Index. Then be sure you don't
go over the GVW limit for your vehicle, including the
weight of the trailer tongue.
Hitches
It's important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are a
few reasons why you'll need the right hitch. Here are
some rules to follow:

If you'll be pulling a trailer that, when loaded, will
weigh more than 4,000 lbs. (1 816 kg), be sure to use
a properly mounted, weight
-distributing hitch and
sway control of the proper size. This equipment is
very important for proper vehicle loading and good
handling when you're driving.

Will you have to make any holes in the body of your
vehicle when you install a trailer hitch?
If you do, then be sure to seal the holes later when
you remove the hitch. If you don't seal them, deadly
carbon monoxide (CO) from your exhaust can get
into your vehicle. See ªCarbon Monoxideº in the
Index. Dirt and water can, too.

4-56 Driving with a Trailer
CAUTION:
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon monoxide
(CO) could come into your vehicle. You can't see
or smell CO. It can cause unconsciousness or
death. See ªEngine Exhaustº in the Index. To
maximize your safety when towing a trailer:

Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.

Keep the rear
-most windows closed.

If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with the
fan on any speed. This will bring fresh,
outside air into your vehicle. Do not use
recirculation because it only recirculates
the air inside your vehicle. See ªComfort
Controlsº in the Index.
Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you'll want to get
to know your rig. Acquaint yourself with the feel of
handling and braking with the added weight of the
trailer. And always keep in mind that the vehicle you are
driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check the trailer hitch and platform
(and attachments), safety chains, electrical connector,
lamps, tires and mirror adjustment. If the trailer has
electric brakes, start your vehicle and trailer moving and
then apply the trailer brake controller by hand to be sure
the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer brakes
are still working.

5-17
Engine Fan Noise
This vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions the clutch is not engaged. This improves
fuel economy and reduces fan noise. Under heavy
vehicle loading, trailer towing, and/or high outside
temperatures, the fan speed increases when the clutch
engages. So you may hear an increase in fan noise.
This is normal and should not be mistaken as the
transmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a few
tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you'd use in a
skid. In any rear blowout, remove your foot from the
accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop
-- well off the road if possible.
If a tire goes flat, the next part shows how to use your
jacking equipment to change a flat tire safely.

5-32
Secure the items and return the rear seat to its
proper position.
A. Handle
B. Wheel WrenchC. Extension
D. Wheel Blocks
and Jack
If You're Stuck: In Sand, Mud,
Ice or Snow
In order to free your vehicle when it is stuck, you will
need to spin the wheels, but you don't want to spin
your wheels too fast. The method known as ªrockingº
can help you get out when you're stuck, but you must
use caution.
CAUTION:
If you let your tires spin at high speed, they can
explode, and you or others could be injured.
And, the transmission or other parts of the
vehicle can overheat. That could cause an engine
compartment fire or other damage. When you're
stuck, spin the wheels as little as possible. Don't
spin the wheels above 35 mph (55 km/h) as shown
on the speedometer.

5-33
NOTICE:
Spinning your wheels can destroy parts of your
vehicle as well as the tires. If you spin the wheels
too fast while shifting your transmission back
and forth, you can destroy your transmission.
For information about using tire chains on your vehicle,
see ªTire Chainsº in the Index.
Rocking Your Vehicle To Get It Out
First, turn your steering wheel left and right. That will
clear the area around your front wheels. If you have a
four
-wheel-drive vehicle, shift into 4HI. Then shift back
and forth between REVERSE (R) and a forward gear,
spinning the wheels as little as possible. Release the
accelerator pedal while you shift, and press lightly on
the accelerator pedal when the transmission is in gear.
By slowly spinning your wheels in the forward and
reverse directions, you will cause a rocking motion that
may free your vehicle. If that doesn't get you out after
a few tries, you may need to be towed out. If you do
need to be towed out, see ªTowing Your Vehicleº in
the Index.

6-
6-1
Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-3 Fuel
6
-5 Fuels in Foreign Countries
6
-6 Filling Your Tank
6
-8 Filling a Portable Fuel Container
6
-8 Checking Things Under the Hood
6
-11 Engine Oil
6
-15 Engine Air Cleaner/Filter
6
-17 Automatic Transmission Fluid
6
-20 Rear Axle
6
-21 Four-Wheel Drive
6
-23 Engine Coolant
6
-26 Radiator Pressure Cap
6
-27 Power Steering Fluid
6
-28 Windshield Washer Fluid
6
-29 Brakes6
-33 Battery
6
-33 Bulb Replacement
6
-36 Windshield Wiper Blade Replacement
6
-38 Tires
6
-46 Appearance Care
6
-47 Cleaning the Inside of Your Vehicle
6
-49 Care of Safety Belts
6
-50 Cleaning the Outside of Your Vehicle
6
-54 GM Vehicle Care/Appearance Materials
6
-55 Vehicle Identification Number (VIN)
6
-55 Service Parts Identification Label
6
-56 Electrical System
6
-63 Replacement Bulbs
6
-63 Capacities and Specifications
6
-64 Normal Maintenance Replacement Parts

6-32
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in the
proper sequence to GM torque specifications.
Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7 of this
manual under Part C ªPeriodic Maintenance Inspections.º
Brake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in pedal
travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you make a brake stop, your disc brakes
adjust for wear.
Replacing Brake System Parts
The braking system on a vehicle is complex. Its many
parts have to be of top quality and work well together if
the vehicle is to have really good braking. Your vehicle
was designed and tested with top
-quality GM brake
parts. When you replace parts of your braking
system
-- for example, when your brake linings wear
down and you need new ones put in
-- be sure you get
new approved GM replacement parts. If you don't, your
brakes may no longer work properly. For example, if
someone puts in brake linings that are wrong for your
vehicle, the balance between your front and rear brakes
can change
-- for the worse. The braking performance
you've come to expect can change in many other ways
if someone puts in the wrong replacement brake parts.

6-38
6. Put the blade assembly pivot in the wiper arm
hook. Pull up until the pivot locking tab locks in the
hook slot.
7. Carefully lower the wiper arm and blade assembly
onto the windshield.
Backglass Wiper Blade Replacement
See ªWindshield Wiper Blade Replacementº in this
section for instructions on how to change the backglass
wiper blade. The backglass wiper blade will not lock
in a vertical position like the windshield wiper blade,
so care should be used when pulling it away from
the vehicle.
Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service, see
your GMC Warranty booklet for details.
CAUTION:
Poorly maintained and improperly used tires
are dangerous.

Overloading your tires can cause
overheating as a result of too much friction.
You could have an air
-out and a serious
accident. See ªLoading Your Vehicleº in
the Index.

Underinflated tires pose the same danger as
overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.

Overinflated tires are more likely to be
cut, punctured or broken by a sudden
impact
-- such as when you hit a pothole.
Keep tires at the recommended pressure.

Worn, old tires can cause accidents. If your
tread is badly worn, or if your tires have
been damaged, replace them.

6-39 Inflation -- Tire Pressure
The Certification/Tire label, which is on the driver's
door edge, above the door latch, shows the correct
inflation pressures for your tires when they're cold.
ªColdº means your vehicle has been sitting for at least
three hours or driven no more than 1 mile (1.6 km).
NOTICE:
Don't let anyone tell you that underinflation or
overinflation is all right. It's not. If your tires
don't have enough air (underinflation), you can
get the following:

Too much flexing

Too much heat

Tire overloading

Bad wear

Bad handling

Bad fuel economy
NOTICE: (Continued)
NOTICE: (Continued)
If your tires have too much air (overinflation),
you can get the following:

Unusual wear

Bad handling

Rough ride

Needless damage from road hazards
When to Check
Check your tires once a month or more. Also, check the
tire pressure of the spare tire.
How to Check
Use a good quality pocket
-type gage to check tire
pressure. You can't tell if your tires are properly inflated
simply by looking at them. Radial tires may look
properly inflated even when they're underinflated.
Be sure to put the valve caps back on the valve
stems. They help prevent leaks by keeping out dirt
and moisture.

6-40 Tire Inspection and Rotation
Tires should be rotated every 6,000 to 8,000 miles
(10 000 to 13 000 km). Any time you notice unusual
wear, rotate your tires as soon as possible and check
wheel alignment. Also check for damaged tires or
wheels. See ªWhen It's Time for New Tiresº and
ªWheel Replacementº later in this section for more
information. Make sure the spare tire is stored securely.
Push, pull, and then try to rotate or turn the tire. If it
moves, use the wheel wrench to tighten the cable. See
ªStoring a Flat or Spare Tire and Toolsº in the Index.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The first
rotation is the most important. See ªScheduled
Maintenance Servicesº in the Index for scheduled
rotation intervals.
When rotating your tires, always use one of the correct
rotation patterns shown here.