brake GMC ENVOY 2002 Workshop Manual

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.

5-18
Changing a Flat Tire
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place. Turn on your hazard
warning flashers.
CAUTION:
Changing a tire can cause an injury. The vehicle
can slip off the jack and roll over you or other
people. You and they could be badly injured.
Find a level place to change your tire. To help
prevent the vehicle from moving:
1. Set the parking brake firmly.
2. Put the shift lever in PARK (P).
3. If you have a four
-wheel-drive vehicle,
be sure the transfer case is in a drive
gear
-- not in NEUTRAL.
CAUTION: (Continued)
CAUTION: (Continued)
4. Turn off the engine.
5. Put the wheel blocks at the front and
rear of the tire farthest away from the
one being changed. That would be the
tire on the other side of the vehicle, at
the opposite end.
The following steps will tell you how to use the jack and
change a tire.

5-28
NOTICE:
Improperly tightened wheel nuts can lead to
brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper
torque specification.
Storing a Flat or Spare Tire and Tools
CAUTION:
Storing a jack, a tire or other equipment in the
passenger compartment of the vehicle could
cause injury. In a sudden stop or collision, loose
equipment could strike someone. Store all these
in the proper place.
CAUTION:
The underbody-mounted spare tire or flat road
tire needs to be stored with the valve stem
pointing up. If the tire is stored with its valve
stem pointing downward, its secondary latch
won't work properly, and the spare tire or flat
road tire could loosen and suddenly fall from
your vehicle. If this happened when your vehicle
was being driven, the tire might contact a person
or another vehicle, causing injury and, of course,
damage to itself as well. Be sure the
underbody
-mounted spare or flat road tire is
stored with its valve stem pointing up.

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

6-8
Filling a Portable Fuel Container
CAUTION:
Never fill a portable fuel container while it is in
your vehicle. Static electricity discharge from the
container can ignite the gasoline vapor. You can
be badly burned and your vehicle damaged if this
occurs. To help avoid injury to you and others:

Dispense gasoline only into
approved containers.

Do not fill a container while it is inside a
vehicle, in a vehicle's trunk, pickup bed or
on any surface other than the ground.

Bring the fill nozzle in contact with the
inside of the fill opening before operating
the nozzle. Contact should be maintained
until the filling is complete.

Don't smoke while pumping gasoline.
Checking Things Under the Hood
CAUTION:
Things that burn can get on hot engine parts and
start a fire. These include liquids like fuel, oil,
coolant, brake fluid, windshield washer and other
fluids, and plastic or rubber. You or others could
be burned. Be careful not to drop or spill things
that will burn onto a hot engine.

6-11
A. Coolant Recovery Tank
B. Engine Air Cleaner/Filter
C. Windshield Washer
Fluid Reservoir
D. Engine Air Cleaner/Filter Indicator
E. Power Steering Fluid Reservoir
F. Automatic Transmission Dipstick
G. Engine Oil Dipstick
H. Radiator Pressure Cap
I. Engine Oil Fill Cap
J. Front Engine Lift Bracket Marked ªGNDº
K. Brake Master Cylinder
L. Battery
M. Engine Compartment Fuse Block
Before closing the hood, be sure all filler caps are on
properly. Then lift the hood to relieve pressure on the
hood prop. Remove the hood prop from its slot in the
hood and return the prop to its retainer. Then pull the
hood down firmly to close. It will latch when dropped
from 6 to 8 inches (15 to 20 cm) without pressing on
the hood.Engine Oil
If the CHECK OIL LEVEL message appears on the
instrument cluster, it means you need to check your
engine oil level right away. For more information, see
ªCheck Oil Level Messageº in the Index.
You should check your engine oil level regularly; this is
an added reminder.
Checking Engine Oil
It's a good idea to check your engine oil every time you
get fuel. In order to get an accurate reading, the oil must
be warm and the vehicle must be on level ground.
The engine oil dipstick
handle is a yellow ring
located in the engine
compartment toward the
passenger's side of the
vehicle. See ªEngine
Compartment Overviewº
in the Index for more
information on location.

6-19
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.

In heavy traffic
-- especially in hot weather.

While pulling a trailer.
To get the right reading, the fluid should be at normal
operating temperature, which is 180F to 200F
(82C to 93C).
Get the vehicle warmed up by driving about
15 miles (24 km) when outside temperatures are above
50F (10C). If it's colder than 50F (10C), drive
the vehicle in THIRD (3) until the engine temperature
gage moves and then remains steady for 10 minutes.
A cold fluid check can be made after the vehicle has
been sitting for eight hours or more with the engine off,
but this is used only as a reference. Let the engine run
at idle for five minutes if outside temperatures are 50F
(10C) or more. If it's colder than 50F (10C), you
may have to idle the engine longer. Should the fluid
level be low during this cold check, you must check the
fluid hot before adding fluid. Checking the fluid hot will
give you a more accurate reading of the fluid level.Checking the Fluid Level
Prepare your vehicle as follows:

Park your vehicle on a level place. Keep the
engine running.

With the parking brake applied, place the shift lever
in PARK (P).

With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK (P).

Let the engine run at idle for three minutes or more.
Then, without shutting off the engine, follow these steps:
Locate the handle with
the transmission and lock
symbols for the automatic
transmission dipstick in
the engine compartment
on the passenger's side
of the vehicle.
See ªEngine Compartment Overviewº in the Index for
more information on location.
1. Flip the handle up and then pull out the dipstick and
wipe it with a clean rag or paper towel.

6-29
Brakes
Brake Fluid
Your brake master cylinder reservoir is filled with
DOT
-3 brake fluid. See ªEngine Compartment
Overviewº in the Index for the location of the reservoir.
There are only two reasons why the brake fluid level in the
reservoir might go down. The first is that the brake fluid
goes down to an acceptable level during normal brake
lining wear. When new linings are put in, the fluid levelgoes back up. The other reason is that fluid is leaking out
of the brake system. If it is, you should have your brake
system fixed, since a leak means that sooner or later your
brakes won't work well, or won't work at all.
So, it isn't a good idea to ªtop offº your brake fluid.
Adding brake fluid won't correct a leak. If you add fluid
when your linings are worn, then you'll have too much
fluid when you get new brake linings. You should add
(or remove) brake fluid, as necessary, only when work is
done on the brake hydraulic system.
CAUTION:
If you have too much brake fluid, it can spill
on the engine. The fluid will burn if the engine
is hot enough. You or others could be burned,
and your vehicle could be damaged. Add brake
fluid only when work is done on the brake
hydraulic system. See ªChecking Brake Fluidº in
this section.
Refer to the Maintenance Schedule to determine when to
check your brake fluid. See ªPeriodic Maintenance
Inspectionsº in the Index.

6-30
Checking Brake Fluid
You can check the brake fluid without taking off the cap.
Just look at the brake fluid reservoir. The fluid level
should be above MIN. If it isn't, have your brake system
checked to see if there is a leak.
After work is done on the brake hydraulic system,
make sure the level is above the MIN but not over the
MAX mark.What to Add
When you do need brake fluid, use only DOT
-3 brake
fluid. Refer to ªRecommended Fluids and Lubricantsº
in the Index. Use new brake fluid from a sealed
container only.
Always clean the brake fluid reservoir cap and the area
around the cap before removing it. This will help keep
dirt from entering the reservoir.
CAUTION:
With the wrong kind of fluid in your brake
system, your brakes may not work well, or they
may not even work at all. This could cause a
crash. Always use the proper brake fluid.

6-31
NOTICE:

Using the wrong fluid can badly damage
brake system parts. For example, just a few
drops of mineral
-based oil, such as engine
oil, in your brake system can damage brake
system parts so badly that they'll have to be
replaced. Don't let someone put in the
wrong kind of fluid.

If you spill brake fluid on your vehicle's
painted surfaces, the paint finish can be
damaged. Be careful not to spill brake fluid
on your vehicle. If you do, wash it off
immediately. See ªAppearance Careº in
the Index.
Brake Wear
Your vehicle has four-wheel disc brakes.
Disc brake pads have built
-in wear indicators that make a
high
-pitched warning sound when the brake pads are
worn and new pads are needed. The sound may come and
go or be heard all the time your vehicle is moving (except
when you are pushing on the brake pedal firmly).
CAUTION:
The brake wear warning sound means that soon
your brakes won't work well. That could lead to
an accident. When you hear the brake wear
warning sound, have your vehicle serviced.
NOTICE:
Continuing to drive with worn-out brake pads
could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
your brakes.