service GMC C-SERIES 1999 User Guide

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A reading in the low pressure zone may be caused by a
dangerously low oil level or other problem.
If you have a Caterpillar

diesel engine, also see your
Caterpillar
Operation & Maintenance Manual.
CAUTION:
Don't keep driving if the oil pressure is low. If
you do, your engine can become so hot that it
catches fire. You or others could be burned.
Check your oil as soon as possible and have your
vehicle serviced.
NOTICE:
Damage to your engine from neglected oil
problems can be costly and is not covered by
your warranty.
Change Oil Light (If Equipped)
The CHANGE OIL light
should come on briefly as a
bulb check when you start
the engine. If the light
doesn't come on, have
it serviced.
If the CHANGE OIL light comes on and stays on after
you start the engine, have the oil changed.
For additional information, see ªEngine Oil, When to
Changeº in the Index. To reset the Oil Life Monitor, see
ªEngine Oil Life Monitorº in the Index.
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3-12 Care of Your Cassette Tape Player
A tape player that is not cleaned regularly can cause
reduced sound quality, ruined cassettes or a damaged
mechanism. Cassette tapes should be stored in their
cases away from contaminants, direct sunlight and
extreme heat. If they aren't, they may not operate
properly or may cause failure of the tape player.
Your tape player should be cleaned regularly after every
50 hours of use. If you notice a reduction in sound
quality, try a known good cassette to see if it is the tape
or the tape player at fault. If this other cassette has no
improvement in sound quality, clean the tape player.
The recommended cleaning method for your cassette
tape player is the use of a scrubbing action,
non
-abrasive cleaning cassette with pads which scrub
the tape head as the hubs of the cleaner cassette turn.
The recommended cleaning cassette is available through
your dealership (GM Part No. 12344789).
When using a scrubbing action, non
-abrasive cleaning
cassette, it is normal for the cassette to eject because
your unit is equipped with a cut tape detection feature
and a cleaning cassette may appear as a broken tape.
If the cleaning cassette ejects, insert the cassette at least
three times to ensure thorough cleaning.You may also choose a non
-scrubbing action, wet-type
cleaner which uses a cassette with a fabric belt to clean
the tape head. This type of cleaning cassette will not
eject on its own. A non
-scrubbing action cleaner may
not clean as thoroughly as the scrubbing type cleaner.
The use of a non
-scrubbing action, dry-type cleaning
cassette is not recommended.
Cassettes are subject to wear and the sound quality may
degrade over time. Always make sure the cassette tape
is in good condition before you have your tape
player serviced.
Fixed Mast Antenna
The fixed mast antenna can withstand most vehicle
washes without being damaged. If the mast should ever
become slightly bent, you can straighten it out by hand.
If the mast is badly bent, as it might be by vandals, you
should replace it.
Check every once in a while to be sure the mast is still
tightened to the cowl.
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4-21
Once you are moving on the freeway, make certain you
allow a reasonable following distance. Expect to move
slightly slower at night.
When you want to leave the freeway, move to the proper
lane well in advance. If you miss your exit, do not,
under any circumstances, stop and back up. Drive on to
the next exit.
The exit ramp can be curved, sometimes quite sharply.
The exit speed for cars
-- but not larger vehicles -- is
usually posted. You should go more slowly.
Reduce your speed according to your speedometer, not
to your sense of motion. After driving for any distance
at higher speeds, you may tend to think you are going
slower than you actually are.
Highway Hypnosis
Is there actually such a condition as ªhighway hypnosisº?
Or is it just plain falling asleep at the wheel? Call it
highway hypnosis, lack of awareness, or whatever.When you drive the vehicle for a long distance, there is
something about an easy stretch of road with the same
scenery, along with the hum of the tires on the road, the
drone of the engine, and the rush of the wind against the
vehicle that can make you sleepy. Don't let it happen to
you! If it does, your vehicle can leave the road in less
than a second, and you could crash and be injured.
What can you do about highway hypnosis? First, be
aware that it can happen.
Then here are some tips:

Make sure your vehicle is well ventilated, with a
comfortably cool interior.

Keep your eyes moving. Scan the road ahead and
to the sides. Check your mirrors and your
instruments frequently.

If you get sleepy, pull off the road into a rest, service
or parking area and take a nap, get some exercise, or
both. For safety, treat drowsiness on the highway as
an emergency.
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5-8
8. Now connect the black
negative (
-) cable to
the good battery's
negative (
-) terminal.
Don't let the other end touch anything until the next
step. The other end of the negative (
-) cable doesn't go
to the dead battery. It goes to a heavy, unpainted, metal
part on the engine, or some other well
-grounded part of
the vehicle with the dead battery.
9. Attach the cable at least
18 inches (45 cm) away
from the dead battery,
but not near engine parts
that move. The electrical
connection is just as
good there, but the
chance of sparks getting
back to the battery is
much less.
10. Now start the vehicle with the good battery and run
the engine for one to two minutes. If your vehicle
has the high idle option, use it.
11. Try to start the vehicle with the dead battery.
If it won't start after a few tries, it probably
needs service.
12. Remove the cables in reverse order to prevent
electrical shorting. Take care that they don't touch
each other or any other metal.
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5-9
A. Heavy Metal Engine Part
B. Good Battery
C. Dead Battery
Towing Your Vehicle
Try to have a GM dealer or a professional towing
service tow your vehicle. They can provide the right
equipment and know
-how to tow it without damage.
Before you do anything, turn on the hazard warning
flashers (if they have not been damaged).
When you call, tell the towing service:

The make, model and year of your vehicle.

Whether you can still move the shift lever.

If there was an accident, what was damaged.
When the towing service arrives, let the tow operator
know that this manual contains detailed towing
instructions. The operator may want to see them.
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5-19 If No Steam Is Coming From Your Engine
If you get an engine overheat warning but see or hear no
steam, the problem may not be too serious. Sometimes
the engine can get a little too hot when you:

Climb a long hill on a hot day.

Stop after high
-speed driving.

Idle for long periods in traffic.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. If you have an air conditioner and it's on, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
3. If you're in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
-- DRIVE (D) for automatic transmissions.
4. If climbing a hill, downshift to raise engine and
fan speeds.If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning doesn't come back on, you can
drive normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there's still no sign of steam, push down the
accelerator until the engine speed is about twice as fast
as normal idle speed for at least three minutes while
you're parked. If you still have the warning, turn off the
engine and get everyone out of the vehicle until it
cools down.
You may decide not to lift the hood but to get service
help right away.
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5-22
CAUTION: (Continued)
Don't run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
NOTICE:
Engine damage from running your engine
without coolant isn't covered by your warranty.
NOTICE:
When adding coolant, it is important that you use
only DEX
-COOL
(silicate-free) coolant.
NOTICE: (Continued)
NOTICE: (Continued)
If coolant other than DEX-COOL is added to the
system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
-- at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the use
of coolant other than DEX
-COOL
is not
covered by your new vehicle warranty.
If there seems to be no leak, start the engine again. See if
the engine cooling fan speed increases when idle speed is
doubled by pushing the accelerator pedal down. If it
doesn't, your vehicle needs service. Turn off the engine.
How to Add Coolant to the Coolant
Recovery Tank
If you haven't found a problem yet, but the coolant level
isn't at or above the HOT LEVEL mark on the vehicle
with the specialty hood, or at or above the COLD LEVEL
mark on the vehicle with the sloped hood, add a 50/50
mixture of clean, drinkable water and DEX
-COOL

engine coolant at the coolant recovery tank. (See ªEngine
Coolantº in the Index for more information.)
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5-28
The coolant level
should be at COLD
ADD or higher. If it
isn't, you may have a
leak in the radiator
hoses, heater hoses,
radiator, water pump
or somewhere else in
the cooling system.
Caterpillar

Diesel
Engine
CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Don't touch them. If you
do, you can be burned.
Don't run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
NOTICE:
Engine damage from running your engine
without coolant isn't covered by your warranty.
If there seems to be no leak, start the engine again. See
if the fan speed increases when idle speed is doubled by
pushing the accelerator pedal down. If it doesn't, your
vehicle needs service. Turn off the engine.
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6-
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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
-4 Fuel (Gasoline Engine)
6
-5 Diesel Fuel Requirements and Fuel System
6
-6 Fuels in Foreign Countries (Gasoline Engines)
6
-7 Filling Your Tank
6
-8 Filling a Portable Fuel Container
6
-9 Checking Things Under the Hood
6
-11 Noise Control System
6
-13 Engine Oil (Gasoline Engine)
6
-17 Engine Oil (Caterpillar
Diesel Engine)
6
-17 Engine Air Cleaner/Filter
6
-18 Automatic Transmission Fluid
6
-19 Manual Transmission Fluid
6
-20 Rear Axle
6
-20 Rear Axle Shift Motor (Option)
6
-21 Radiator Pressure Cap (Gasoline Engines)
6
-22 Surge Tank Pressure Cap (Diesel Engines)
6
-22 Thermostat6
-23 Engine Coolant (Gasoline Engine)
6
-27 Engine Coolant (Caterpillar
Diesel Engine)
6
-28 Power Steering Fluid
6
-29 Windshield Washer Fluid
6
-30 Brakes
6
-36 Electric/Hydraulic Parking Brake Fluid
6
-42 Battery
6
-44 Other Service Items
6
-48 Tires
6
-59 Appearance Care
6
-59 Cleaning the Inside of Your Vehicle
6
-63 Cleaning the Outside Your Vehicle
6
-66 GM Vehicle Care/Appearance Materials
6
-67 Vehicle Identification Number (VIN)
6
-67 Service Parts Identification Label
6
-68 Electrical System
6
-74 Capacities and Specifications
6
-77 Air Conditioning Refrigerants
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6-2
Service
Your dealer knows your vehicle best and wants you to
be happy with it. We hope you'll go to your dealer for
all your service needs. You'll get genuine GM parts and
GM
-trained and supported service people.
We hope you'll want to keep your GM vehicle all GM.
Genuine GM parts have one of these marks:
Doing Your Own Service Work
If you want to do some of your own service work, you'll
want to use the proper service manual. It tells you much
more about how to service your vehicle than this manual
can. To order the proper service manual, see ªService
and Owner Publicationsº in the Index.
You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. See ªMaintenance Recordº in the Index.
CAUTION:
You can be injured and your vehicle could be
damaged if you try to do service work on a
vehicle without knowing enough about it.

Be sure you have sufficient knowledge,
experience, the proper replacement parts
and tools before you attempt any vehicle
maintenance task.

Be sure to use the proper nuts, bolts and
other fasteners. ªEnglishº and ªmetricº
fasteners can be easily confused. If you use
the wrong fasteners, parts can later break
or fall off. You could be hurt.
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