tow GMC ENVOY 1999 Workshop Manual

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6-13 Engine Oil Additives
Don't add anything to your oil. Your dealer is ready to
advise if you think something should be added.
When to Change Engine Oil
If any one of these is true for you, use the short trip/city
maintenance schedule:

Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures are below freezing.

Most trips include extensive idling (such as frequent
driving in stop
-and-go traffic).

You operate your vehicle in dusty areas or
off
-road frequently.

You frequently tow a trailer or use a carrier on top of
your vehicle.

The vehicle is used for delivery service, police, taxi
or other commercial application.
Driving under these conditions causes engine oil to
break down sooner. If any one of these is true for your
vehicle, then you need to change your oil and filter
every 3,000 miles (5 000 km) or 3 months
-- whichever
occurs first.If none of them is true, use the long trip/highway
maintenance schedule. Change the oil and filter every
7,500 miles (12 500 km) or 12 months
-- whichever
occurs first. Driving a vehicle with a fully warmed
engine under highway conditions causes engine oil to
break down slower.
Remote Oil Filter
The access door for the
remote oil filter is in the
steering linkage shield
assembly located under the
radiator support. Twist the
screw to unlock or lock the
door. If you open the door,
make sure it is securely
closed when you
are finished.
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6-15
CAUTION:
Operating the engine with the air cleaner/filter
off can cause you or others to be burned. The air
cleaner not only cleans the air, it stops flame if
the engine backfires. If it isn't there, and the
engine backfires, you could be burned. Don't
drive with it off, and be careful working on the
engine with the air cleaner/filter off.
NOTICE:
If the air cleaner/filter is off, a backfire can cause
a damaging engine fire. And, dirt can easily get
into your engine, which will damage it. Always
have the air cleaner/filter in place when
you're driving.
Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 15,000 miles
(25 000 km) if the vehicle is mainly driven under one or
more of these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.

In hilly or mountainous terrain.

When doing frequent trailer towing.

Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these
conditions, change the fluid and filter every
50,000 miles (83 000 km).
See ªScheduled Maintenance Servicesº in the Index.
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6-17
Checking the Fluid Level

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:
1. The transmission
dipstick is located
at the rear of the
engine compartment.Flip the handle up and then pull out the dipstick and
wipe it with a clean rag or paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again.
3. Check both sides of the dipstick, and read the lower
level. The fluid level must be in the COLD area for a
cold check or in the HOT area or cross
-hatched area
for a hot check.
4. If the fluid level is in the acceptable range, push the
dipstick back in all the way; then flip the handle
down to lock the dipstick in place.
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6-40
CAUTION:
Rust or dirt on a wheel, or on the parts to which
it is fastened, can make wheel nuts become loose
after a time. The wheel could come off and cause
an accident. When you change a wheel, remove
any rust or dirt from places where the wheel
attaches to the vehicle. In an emergency, you can
use a cloth or a paper towel to do this; but be
sure to use a scraper or wire brush later, if you
need to, to get all the rust or dirt off. (See
ªChanging a Flat Tireº in the Index.)
When It's Time for New Tires
One way to tell when it's
time for new tires is to
check the treadwear
indicators, which will
appear when your tires have
only 1/16 inch (1.6 mm) or
less of tread remaining.
You need a new tire if any of the following statements
are true:

You can see the indicators at three or more places
around the tire.

You can see cord or fabric showing through the
tire's rubber.

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.
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6-46
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/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.

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.
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6-50
Cleaning the Outside of Your Vehicle
The paint finish on your vehicle provides beauty, depth
of color, gloss retention and durability.
Washing Your Vehicle
The best way to preserve your vehicle's finish is to
keep it clean by washing it often with lukewarm or
cold water.
Don't wash your vehicle in the direct rays of the sun.
Use a car washing soap. Don't use strong soaps or
chemical detergents. Be sure to rinse the vehicle well,
removing all soap residue completely. You can get
GM
-approved cleaning products from your dealer. (See
ªAppearance Care and Materialsº in the Index.) Don't
use cleaning agents that are petroleum based, or that
contain acid or abrasives. All cleaning agents should be
flushed promptly and not allowed to dry on the surface,
or they could stain. Dry the finish with a soft, clean
chamois or an all
-cotton towel to avoid surface
scratches and water spotting.
High pressure car washes may cause water to enter
your vehicle.Cleaning Exterior Lamps/Lenses
Use lukewarm or cold water, a soft cloth and a car
washing soap to clean exterior lamps and lenses. Follow
instructions under ªWashing Your Vehicle.º
Finish Care
Occasional waxing or mild polishing of your vehicle by
hand may be necessary to remove residue from the paint
finish. You can get GM
-approved cleaning products
from your dealer. (See ªAppearance Care and Materialsº
in the Index.)
Your vehicle has a ªbasecoat/clearcoatº paint finish.
The clearcoat gives more depth and gloss to the colored
basecoat. Always use waxes and polishes that are
non
-abrasive and made for a basecoat/clearcoat
paint finish.
NOTICE:
Machine compounding or aggressive polishing on
a basecoat/clearcoat paint finish may dull the
finish or leave swirl marks.
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6-51
Foreign materials such as calcium chloride and other
salts, ice melting agents, road oil and tar, tree sap, bird
droppings, chemicals from industrial chimneys, etc., can
damage your vehicle's finish if they remain on painted
surfaces. Wash the vehicle as soon as possible. If
necessary, use non
-abrasive cleaners that are marked
safe for painted surfaces to remove foreign matter.
Exterior painted surfaces are subject to aging, weather
and chemical fallout that can take their toll over a period
of years. You can help to keep the paint finish looking
new by keeping your vehicle garaged or covered
whenever possible.
Cleaning Aluminum Wheels
Keep your wheels clean using a soft clean cloth with
mild soap and water. Rinse with clean water. After
rinsing thoroughly, dry with a soft clean towel. A wax
may then be applied.
The surface of these wheels is similar to the painted
surface of your vehicle. Don't use strong soaps,
chemicals, abrasive polishes, abrasive cleaners, cleaners
with acid or abrasive cleaning brushes on them because
you could damage the surface. Do not use chrome polish
on any wheels other than chrome
-plated wheels.Don't take your vehicle through an automatic car wash
that has silicon carbide tire cleaning brushes. These
brushes can also damage the surface of these wheels.
Cleaning Tires
To clean your tires, use a stiff brush with a tire cleaner.
NOTICE:
When applying a tire dressing always take care to
wipe off any overspray or splash from all painted
surfaces on the body or wheels of the vehicle.
Petroleum
-based products may damage the paint
finish and tires.
Sheet Metal Damage
If your vehicle is damaged and requires sheet metal
repair or replacement, make sure the body repair shop
applies anti
-corrosion material to the parts repaired or
replaced to restore corrosion protection.
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Scheduled Maintenance
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7-5
Short Trip/City Definition
Follow the Short Trip/City Scheduled Maintenance if
any one of these conditions is true for your vehicle:

Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures are below freezing.

Most trips include extensive idling (such as frequent
driving in stop
-and-go traffic).

You operate your vehicle in dusty areas or
off
-road frequently.

You frequently tow a trailer or use a carrier on top of
your vehicle.

If the vehicle is used for delivery service, police, taxi
or other commercial application.
One of the reasons you should follow this schedule if
you operate your vehicle under any of these conditions
is that these conditions cause engine oil to break
down sooner.
Short Trip/City Intervals
Every 3,000 Miles (5 000 km): Engine Oil and Filter
Change (or 3 months, whichever occurs first). Chassis
Lubrication (or 3 months, whichever occurs first). Drive
Axle Service (or 3 months, whichever occurs first).
Every 6,000 Miles (10 000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Air Cleaner Filter
Inspection, if driving in dusty conditions. Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Air Cleaner Filter
Replacement. Fuel Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection. Fuel Tank, Cap and
Lines Inspection.
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Scheduled Maintenance
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7-6
Short Trip/City Intervals
Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every 60 months, whichever occurs first).
These intervals only summarize maintenance services.
Be sure to follow the complete scheduled maintenance
on the following pages.
Long Trip/Highway Definition
Follow this scheduled maintenance only if none of the
conditions from the Short Trip/City Scheduled
Maintenance is true. Do not use this schedule if the
vehicle is used for trailer towing, driven in a dusty area
or used off paved roads. Use the Short Trip/City
schedule for these conditions.
Driving a vehicle with a fully warmed engine under
highway conditions causes engine oil to break
down slower.
Long Trip/Highway Intervals
Every 7,500 Miles (12 500 km): Engine Oil and Filter
Change (or every 12 months, whichever occurs first).
Chassis Lubrication (or every 12 months, whichever
occurs first). Drive Axle Service. Tire Rotation.
Every 15,000 Miles (25 000 km): Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Fuel Filter
Replacement. Air Cleaner Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection. Fuel Tank, Cap and
Lines Inspection.
Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every 60 months, whichever occurs first).
These intervals only summarize maintenance services.
Be sure to follow the complete scheduled maintenance
on the following pages.
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Short Trip/City Scheduled Maintenance
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7-7
The services shown in this schedule up to 100,000 miles
(166 000 km) should be performed after 100,000 miles
(166 000 km) at the same intervals. The services shown
at 150,000 miles (240 000 km) should be performed at
the same interval after 150,000 miles (240 000 km).
See ªOwner Checks and Servicesº and ªPeriodic
Maintenance Inspectionsº following.
Footnotes
 The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to the
completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the maintenance
be recorded.# Lubricate the front suspension, ball joints, steering
linkage, parking brake cable guides, propshaft splines,
universal joints and brake pedal springs.
+ A good time to check your brakes is during tire
rotation. See ªBrake System Inspectionº under ªPeriodic
Maintenance Inspectionsº in Part C of this schedule.
** Drive axle service (see ªRecommended Fluids and
Lubricantsº in the Index for proper lubricant to use):

Locking Differential -- Drain fluid and refill at first
engine oil change. At subsequent oil changes, check
fluid level and add fluid as needed. If driving in
dusty areas or towing a trailer, drain fluid and refill
every 15,000 miles (25 000 km).

More frequent lubrication may be required for
heavy
-duty or off-road use.
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