1999 GMC YUKON Owner's Manual

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6-43

The tread or sidewall is cracked, cut or snagged deep
enough to show cord or fabric.

The tire has a bump, bulge or split.

The tire has a puncture, cut or other damage that
can't be repaired well because of the size or location
of the damage.
Buying New Tires
To find out what kind and size of tires you need, look at
the Certification/Tire label.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specification (TPC Spec)
number on each tire's sidewall. When you get new tires,
get ones with that same TPC Spec number. That way
your vehicle will continue to have tires that are designed
to give proper endurance, handling, speed rating,
traction, ride and other things during normal service on
your vehicle. If your tires have an all
-season tread
design, the TPC number will be followed by an ªMSº
(for mud and snow).
If you ever replace your tires with those not having a
TPC Spec number, make sure they are the same size,
load range, speed rating and construction type (bias,
bias
-belted or radial) as your original tires.
CAUTION:
Mixing tires could cause you to lose control while
driving. If you mix tires of different sizes or types
(radial and bias
-belted tires), the vehicle may not
handle properly, and you could have a crash.
Using tires of different sizes may also cause
damage to your vehicle. Be sure to use the same
size and type tires on all wheels.
CAUTION:
If you use bias-ply tires on your vehicle, the
wheel rim flanges could develop cracks after
many miles of driving. A tire and/or wheel could
fail suddenly, causing a crash. Use only radial
-ply
tires with the wheels on your vehicle.

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6-44 Uniform Tire Quality Grading
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance. (This
applies only to vehicles sold in the United States.) The
grades are molded on the sidewalls of most passenger
car tires. The Uniform Tire Quality Grading system does
not apply to deep tread, winter
-type snow tires,
space
-saver or temporary use spare tires, tires with
nominal rim diameters of 10 to 12 inches (25 to 30 cm),
or to some limited
-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to Federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.
Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specified government test course. For
example, a tire graded 150 would wear one and a half
(1 1/2) times as well on the government course as a tire
graded 100. The relative performance of tires dependsupon the actual conditions of their use, however, and
may depart significantly from the norm due to variations
in driving habits, service practices and differences in
road characteristics and climate.
Traction
-- AA, A, B, C
The traction grades, from highest to lowest, are AA, A,
B, and C. Those grades represent the tire's ability to stop
on wet pavement as measured under controlled
conditions on specified government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight
-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.
Temperature
-- A, B, C
The temperature grades are A (the highest), B, and C,
representing the tire's resistance to the generation of
heat and its ability to dissipate heat when tested under
controlled conditions on a specified indoor laboratory
test wheel. Sustained high temperature can cause the
material of the tire to degenerate and reduce tire life, and
excessive temperature can lead to sudden tire failure.
The grade C corresponds to a level of performance
which all passenger car tires must meet under the

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6-45
Federal Motor Vehicle Safety Standard No. 109. Grades
B and A represent higher levels of performance on the
laboratory test wheel than the minimum required by law.
Warning: The temperature grade for this tire is
established for a tire that is properly inflated and not
overloaded. Excessive speed, underinflation, or
excessive loading, either separately or in combination,
can cause heat buildup and possible tire failure.
Wheel Alignment and Tire Balance
The wheels on your vehicle were aligned and balanced
carefully at the factory to give you the longest tire life
and best overall performance.
Scheduled wheel alignment and wheel balancing are not
needed. However, if you notice unusual tire wear or
your vehicle pulling one way or the other, the alignment
may need to be reset. If you notice your vehicle
vibrating when driving on a smooth road, your wheels
may need to be rebalanced.
Wheel Replacement
Replace any wheel that is bent, cracked, or badly rusted
or corroded. If wheel nuts keep coming loose, the wheel,
wheel bolts and wheel nuts should be replaced. If the
wheel leaks air, replace it (except some aluminumwheels, which can sometimes be repaired). See your
dealer if any of these conditions exist.
Your dealer will know the kind of wheel you need.
Each new wheel should have the same load
-carrying
capacity, diameter, width, offset and be mounted the
same way as the one it replaces.
If you need to replace any of your wheels, wheel bolts
or wheel nuts, replace them only with new GM original
equipment parts. This way, you will be sure to have the
right wheel, wheel bolts and wheel nuts for your vehicle.
CAUTION:
Using the wrong replacement wheels, wheel bolts
or wheel nuts on your vehicle can be dangerous.
It could affect the braking and handling of your
vehicle, make your tires lose air and make you
lose control. You could have a collision in which
you or others could be injured. Always use the
correct wheel, wheel bolts and wheel nuts
for replacement.

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6-46
NOTICE:
The wrong wheel can also cause problems with
bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper
height, vehicle ground clearance and tire or tire
chain clearance to the body and chassis.
See ªChanging a Flat Tireº in the Index for
more information.
Used Replacement Wheels
CAUTION:
Putting a used wheel on your vehicle is
dangerous. You can't know how it's been used or
how far it's been driven. It could fail suddenly
and cause an accident. If you have to replace a
wheel, use a new GM original equipment wheel.
Tire Chains
NOTICE:
Don't use tire chains. They can damage your
vehicle because there's not enough clearance.
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
conditions. Follow that manufacturer's
instructions. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it's contacting your vehicle, and don't
spin your wheels.
If you do find traction devices that will fit, install
them on the rear tires.

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Appearance Care
Remember, cleaning products can be hazardous. Some
are toxic. Others can burst into flame if you strike a
match or get them on a hot part of the vehicle. Some are
dangerous if you breathe their fumes in a closed space.
When you use anything from a container to clean your
vehicle, be sure to follow the manufacturer's warnings
and instructions. And always open your doors or
windows when you're cleaning the inside.
Never use these to clean your vehicle:

Gasoline

Benzene

Naphtha

Carbon Tetrachloride

Acetone

Paint Thinner

Turpentine

Lacquer Thinner

Nail Polish Remover
They can all be hazardous
-- some more than
others
-- and they can all damage your vehicle, too.Don't use any of these unless this manual says you can.
In many uses, these will damage your vehicle:

Alcohol

Laundry Soap

Bleach

Reducing Agents
Cleaning the Inside of Your Vehicle
Use a vacuum cleaner often to get rid of dust and loose
dirt. Wipe vinyl, leather, plastic and painted surfaces
with a clean, damp cloth.
Cleaning of Fabric and Carpet
Your dealer has two cleaners, Multi-Purpose Interior
Cleaner and Capture Non
-Solvent Dry Spot and Soil
Remover for cleaning fabric and carpet. They will clean
normal spots and stains very well. You can get
GM
-approved cleaning products from your dealer. (See
ªAppearance Care and Materialsº in the Index.)
Here are some cleaning tips:

Always read the instructions on the cleaner label.

Clean up stains as soon as you can
-- before they set.

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Carefully scrape off any excess stain.

Use a clean cloth or sponge, and change to a clean
area often. A soft brush may be used if stains
are stubborn.

If a ring forms on fabric after spot cleaning, clean the
entire area immediately or it will set.
Using Multi-Purpose Interior Cleaner
on Fabric
1. Vacuum and brush the area to remove any loose dirt.
2. Always clean a whole trim panel or section. Mask
surrounding trim along stitch or welt lines.
3. Mix powdered cleaner following the directions on
the container label to form thick suds.
4. Use suds only and apply with a clean sponge. Don't
saturate the material and don't rub it roughly.
5. As soon as you've cleaned the section, use a sponge
to remove the suds.
6. Wipe cleaned area with a clean, damp towel or cloth.
7. Wipe with a clean cloth and let dry.
Special Fabric Cleaning Problems
Stains caused by such things as catsup, coffee (black),
egg, fruit, fruit juice, milk, soft drinks, vomit, urine and
blood can be removed as follows:
1. Carefully scrape off excess stain, then sponge the
soiled area with cool water.
2. If a stain remains, follow the multi
-purpose interior
cleaner instructions described earlier.
3. If an odor lingers after cleaning vomit or urine,
treat the area with a water/baking soda solution:
1 teaspoon (5 ml) of baking soda to 1 cup (250 ml)
of lukewarm water.
4. Let dry.
Stains caused by candy, ice cream, mayonnaise, chili
sauce and unknown stains can be removed as follows:
1. Carefully scrape off excess stain.
2. First, clean with cool water and allow to
dry completely.
3. If a stain remains, follow instructions for
Multi
-Purpose Interior Cleaner.

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6-49 Fabric Protection
Your vehicle has carpet that has been treated with
Scotchgard Fabric Protector, a 3M product. It protects
fabrics by repelling oil and water, which are the carriers
of most stains. Even with this protection, you still need
to clean your carpet often to keep it looking new.
Further information on cleaning is available by calling
1
-800-433-3296 (in Minnesota, 1-800-642-6167).
Cleaning Vinyl
Use warm water and a clean cloth.

Rub with a clean, damp cloth to remove dirt. You
may have to do it more than once.

Things like tar, asphalt and shoe polish will stain if
you don't get them off quickly. Use a clean cloth
and a vinyl/leather cleaner. See your dealer for
this product.
Cleaning Leather
Use a soft cloth with lukewarm water and a mild soap or
saddle soap and wipe dry with a soft cloth. Then, let the
leather dry naturally. Do not use heat to dry.

For stubborn stains, use a leather cleaner. See your
dealer for this product.
Never use oils, varnishes, solvent
-based or abrasive
cleaners, furniture polish or shoe polish on leather.

Soiled or stained leather should be cleaned
immediately. If dirt is allowed to work into the
finish, it can harm the leather.
Cleaning the Top of the Instrument Panel
Use only mild soap and water to clean the top surfaces
of the instrument panel. Sprays containing silicones or
waxes may cause annoying reflections in the windshield
and even make it difficult to see through the windshield
under certain conditions.
Cleaning Interior Plastic Components
Use only a mild soap and water solution on a soft cloth or
sponge. Commercial cleaners may affect the surface finish.
Cleaning Wood Panels
Use a clean cloth moistened in warm, soapy water (use
mild dish washing soap). Dry the wood immediately
with a clean cloth.
Cleaning Speaker Covers
Vacuum around a speaker cover gently, so that the
speaker won't be damaged. Clean spots with just water
and mild soap.

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Care of Safety Belts
Keep belts clean and dry.
CAUTION:
Do not bleach or dye safety belts. If you do, it
may severely weaken them. In a crash, they
might not be able to provide adequate protection.
Clean safety belts only with mild soap and
lukewarm water.
Cleaning Glass Surfaces
Glass should be cleaned often. GM Glass Cleaner or a
liquid household glass cleaner will remove normal
tobacco smoke and dust films on interior glass. (See
ªAppearance Care and Materialsº in the Index.)
Don't use abrasive cleaners on glass, because they may
cause scratches. Avoid placing decals on the inside rear
window, since they may have to be scraped off later. If
abrasive cleaners are used on the inside of the rear
window, an electric defogger element may be damaged.
Any temporary license should not be attached across the
defogger grid.
Cleaning the Outside of the Windshield,
Backglass and Wiper Blades
If the windshield is not clear after using the windshield
washer, or if the wiper blade chatters when running, wax,
sap or other material may be on the blade or windshield.
Clean the outside of the windshield with GM
Windshield Cleaner, Bon Ami

Powder (non-scratching
glass cleaning powder), GM Part No. 1050011. The
windshield is clean if beads do not form when you rinse
it with water.
Grime from the windshield will stick to the wiper blades
and affect their performance. Clean the blade by wiping
vigorously with a cloth soaked in full
-strength windshield
washer solvent. Then rinse the blade with water.
Check the wiper blades and clean them as necessary;
replace blades that look worn.
Weatherstrips
Silicone grease on weatherstrips will make them last
longer, seal better, and not stick or squeak. Apply
silicone grease with a clean cloth at least every six
months. During very cold, damp weather more frequent
application may be required. (See ªRecommended
Fluids and Lubricantsº in the Index.)