1999 GMC C-SERIES air condition

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7-18 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.
(1) = If your vehicle has an Allison automatic
transmission, your GM Owner's Manual is
supplemented by an Allison Transmission Operator's
Manual. Always refer to these manuals for related
maintenance services.
(2) = Check the fluid level in the manual transmission.
(3) = An Emission Control Service.
(4) = A Noise Emission Control Device.
(5) = Applies only to vehicles sold in the United States.
(6) = Check fluid level in brake master cylinder, clutch
master cylinder (if equipped), power steering pump,
axle, transmission and hydraulic spring parking brake
pump (if equipped). A low fluid level in the brake
master cylinder can indicate worn brake linings and
should be checked accordingly.(7) = Inspect brake lines and hoses for proper hook
-up,
binding, leaks, cracks, chafing, etc. Inspect disc brake
pads for wear and rotors for surface condition. Check
brake pedal for excessive free play or travel (or every
6 months, whichever occurs first) and have serviced if
needed. Check brakes more often if driving habits and
conditions result in frequent braking.
(8) = Inspect hydraulic parking brake drum and linings
for wear or cracks and check linkage and adjustment.
Check spring brake actuator and pump for leaks.
Note: The spring brake section of the actuator is
non
-serviceable.
(9) = This vehicle has an Engine Oil Life Monitor. This
monitor will show you when to change the engine oil
and filter
-- usually between 3,000 miles (5 000 km) and
7,500 miles (12 500 km) since your last oil change.
Under severe conditions, the indicator may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 7,500 miles (12 500 km) or 12 months
without an oil and filter change.
The system won't detect dust in the oil. So if you drive
in a dusty area, be sure to change your oil and filter
every 3,000 miles (5 000 km) or sooner if the Change
Oil Light comes on. Remember to reset the Oil Life
Monitor whenever the oil is changed. For more
information, see ªChange Oil Lightº in the Index.
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7-19
(10) = Check clutch pedal for free travel. Press pedal
by hand until resistance is felt. Free travel should be
maintained at 1.5 to 2 inches (38 to 51 mm) measured
at the clutch pedal pad. Make checks at 3,000 miles
(5 000 km) and 6,000 miles (10 000 km) and then every
6,000 miles (10 000 km) thereafter.
(11) = Inspect rear axle air shift motor for fluid leaks.
Remove plug to check fluid level. Inspect air lines and
hoses for proper hook
-up, binding, leaks, etc. Inspect at
3,000 miles (5 000 km) and 24,000 miles (40 000 km)
and then every 24,000 miles (40 000 km) thereafter.
(12) = Chassis Lubrication Service: Lubricate all grease
fittings in front suspension, front axle and steering
linkage. DO NOT lubricate kingpin bushings with air
pressure equipment; instead, use a hand grease gun to
ensure complete purge and eliminate sealer cap
distortion. Lubricate transmission and shift linkage,
hood latches and hood hinges, parking brake lever pivot,
clevis pins and linkage, disc brake caliper rails, clutch
linkage and release bearing (if equipped), propeller shaft
slip joint, universal joint, brake camshaft bracket, slack
adjusters, pedal shaft, clutch cross shaft and clutch pedal
springs. Lubricate suspension, axle and steering linkage
more often when operating under dusty or muddy
conditions and in excessive off
-road use.(13) = Check steering system:

Look for damaged, loose or missing parts. Also
look for parts showing signs of wear or lack of
lubrication. Replace parts as needed. Also check
steering gear mounting bolts, pitman arm nut, gear
housing upper cover and side cover attaching bolts,
steering column mounting bolts and cardan
joint clamp bolts; tighten if necessary.
(See service manual.)

Inspect power steering hoses, tubes and fittings for
leaks. Hoses and lines must not be twisted, kinked or
tightly bent. Make sure clips, clamps, supporting
tubes and hoses are in place and properly secured.

Check steering gear for leakage around pitman shaft
and housing. If leakage is evident (lubricant
oozing out, not just oily film), leak should be
corrected immediately.
(14) = Check front and rear suspension. Look for
damaged, loose or missing parts or parts showing signs
of wear or lack of lubrication. Replace parts as needed.
(15) = Adjust tire pressures as indicated on the
Certification/Tire label for optimum tire life. See ªTiresº
in the Index for further details. Check tires for excessive
or abnormal wear or damage. Also check for damaged
wheels. Replace wheels and/or tires as needed.
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7-20
(16) = Check spring-to-axle U-bolts and shackle bolts
for proper torque. See the service manual for torque
sequence and specifications. When parts are replaced,
the torque must be checked and adjusted more often
during the first 6,000 miles (10 000 km). Check torque
at 500 miles (800 km) and 2,000 miles (3 000 km) after
first use of parts.
(17) = Check complete exhaust system and cab areas
near the exhaust system for broken, damaged, missing or
out
-of-position parts. Also inspect for open seams,
holes, loose connections or other conditions which could
let exhaust fumes seep into the driver compartment.
Needed repairs should be made at once. To help
maintain system integrity, replace exhaust pipes
whenever a new muffler is put on.
(18) = Check all engine drive belts for cracks, fraying,
wear and proper tension. Adjust or replace as needed.
(19) = Check throttle linkage for damaged or missing
parts (including throttle return springs), interference or
binding. Fix any problems at once. Do not lubricate
accelerator and cruise control cables.
(20) = With the engine off and below normal operating
temperature, check to see that the thermostatically
controlled engine cooling fan can be rotated by hand on
viscous
-operated drives. Replace as needed.(21) = Check shields and underhood insulation for
damage or looseness. Adjust or replace as needed.
(22) = Lubricate caliper housing, caliper support spring
and caliper support key.
(23) = Wheel bearing service:

Grease type
-- Clean, inspect and lubricate with the
proper wheel bearing grease at designated intervals
or when hubs are removed. See ªRecommended
Fluids and Lubricantsº in the Index.

Oil
-filled type -- Some wheel bearings are lubricated
by rear axle lubricant. When you have oil
-filled
hubs, use lubricant identical to that used in your rear
axle. Lubricant change intervals are the same for
front and rear axles. However, you must maintain oil
level at the OIL LEVEL mark between change
intervals. See ªRecommended Fluids and
Lubricantsº in the Index.
(24) = Check the air intake system installation to see
that gaskets are seated properly and all hose
connections, fasteners and other components are tight.
For gasoline engines, also check to be sure the air
cleaner housing is properly seated, that the cover fits
tightly and that the wing nut is tight. Tighten
connections and fasteners or replace parts as required.
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7-21
(25) = Check thermostatically controlled air cleaner
installation to make certain that all ducts are connected and
correctly installed. Also, check valve for proper operation.
(26) = Evaporative Control System Service (if equipped):
Check all fuel and vapor lines and hoses for proper
connections and correct routing (or every 24 months,
whichever occurs first). Replace parts as needed.
(27) = Replace air cleaner filter (or every 24 months,
whichever occurs first). Replace filter more often if
driving in dusty conditions. Ask your dealer for the
proper replacement intervals for your driving conditions.
(28) = Replace spark plugs. Inspect wires for damage.
Check the wire boot and boot heat shield fit at spark
plugs and coil. Replace parts as needed.
(30) = Check the fuel tank, fuel cap and fuel lines for
damage which could cause leakage. Inspect fuel cap for
correct sealing ability and any indications of damage.
Check fuel cap gasket for even filler neck imprint.
Replace parts as needed.
(31) = Check EGR system as described in the service
manual. See ªService and Owner Publicationsº in the Index.
(32) = Inspect Electronic Vacuum Regulator Valve
(EVRV) filter for excessive contamination or plugging.
If needed, clean filter with solution of soap and water,
let dry and install.(33) = Check the PCV system for proper operation and
clean PCV valve. Replace hoses as needed.
(34) = Replace PCV valve and blow out the PCV valve
hose with compressed air. Replace hoses as needed.
(35) = Drain, flush and refill cooling system. See
ªRecommended Fluids and Lubricantsº in the Index for
what to use. Inspect hoses. Clean radiator, condenser,
pressure cap and neck. Pressure test cooling system and
pressure cap. For Caterpillar
 diesel engines, always refer
to the Caterpillar Diesel Engine Operation & Maintenance
Manual for coolant recommendations and change intervals.
(37) = Rear axle service: Change the lubricant. See
ªRecommended Fluids and Lubricantsº in the Index.
(38) = Front axle service: Re
-pack upper kingpin
roller bearing.
(39) = Air brake service:

Inspect brake lines and hoses for proper hook
-up,
binding, leaks, cracks, chafing, etc. Inspect drum
brake linings for wear or cracks. Inspect other brake
parts at each wheel, including drums, wheel cylinders
and piston heat shields and boots. Check brake pedal
for excessive free play or travel (or every 6 months,
whichever occurs first) and have serviced if needed.
Check brakes more often if driving habits and
conditions result in frequent braking.
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7-25
Starter Switch Check
CAUTION:
When you are doing this check, the vehicle could
move suddenly. If it does, you or others could be
injured. Follow the steps below.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake (see ªParking
Brakeº in the Index if necessary) and the
regular brakes.
NOTE: Do not use the accelerator pedal, and be
ready to turn off the engine immediately if it starts.
3. On automatic transmission vehicles, try to start the
engine in each gear. The starter should work only in
PARK (P), if equipped, or NEUTRAL (N). If the
starter works in any other position, your vehicle
needs service.Automatic Transmission Shift Indicator Check
Check that the indicator points to the gear chosen.
Steering Check
Be alert for any changes in steering action, abnormal
front tire wear or steering wheel position. An inspection
or service is needed when the steering wheel is harder to
turn or has too much free play, or if there are strange
sounds when turning or parking.
Brake System Check
Be alert to illumination of the low air warning lamp or
for the tone alarm, or changes in braking action, such as
repeated pulling to one side, unusual sounds when
braking or increased brake pedal travel. Make sure air
brake system reservoirs are drained daily with full
system air pressure, and check system for leaks. Any of
these conditions could indicate the need for brake
system inspection and/or service.
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7-26
Engine Cooling System Service
Inspect the hoses and have them replaced if they are
cracked, swollen or deteriorated. Inspect all pipes,
fittings and clamps; replace as needed. Clean the outside
of the radiator and air conditioning condenser. To help
ensure proper operation, a pressure test of the cooling
system and pressure cap is recommended at least once
a year.
Exhaust System Check
Be alert for any changes in the sound of the exhaust
system or any smell of fumes. These are signs the
system may be leaking. Have it checked and/or repaired
at once. Refer to ªEngine Exhaustº and ªRunning Your
Engine While You're Parkedº in the Index.
Windshield Wipers and Washers Check
Check operation and condition of the wiper blades.
Check the flow of the washer spray.
Defroster Check
Move the control to the defrost symbol and the fan to HI
or the high symbol. Then check the airflow from the
ducts at the inside base of the windshield.Mirrors and Sun Visors Check
Check that friction joints hold mirrors and sun visors
in place.
Seat Adjuster Check
When adjusting a manual seat, be sure seat adjusters
latch by attempting to move the seat after latching.
Lamps Check
Check panel lighting, warning lights, indicator lights
and interior lamps. On the outside, check: license plate
lamps, sidemarker lamps, reflectors or lights on outside
mirrors, headlamps, parking lamps, identification and
clearance lamps, taillamps, brake lamps, turn signals,
backup lamps and hazard warning flashers. Have
headlamp aim checked at once if beams seem
improperly aimed.
Glass, Mirrors, Lamps and/or Reflectors
Condition Check
Look for broken, scratched, dirty or damaged glass,
mirrors, lamps or reflectors that could reduce the view
or visibility or cause injury. Replace, clean or
repair promptly.
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9-1
Section 9 Index
A
ir
Brake System Warning Light 2-59 . . . . . . . . . . . . . . . . . . . .
Cleaner 6-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cleaner Filter 6-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Compressor Filter 6-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conditioning 3-5, 6-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conditioning Refrigerants 6-77 . . . . . . . . . . . . . . . . . . . . . .
Dryer 6-34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter Restriction Indicator 6-17 . . . . . . . . . . . . . . . . . . . . . .
Suspension 2-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Brake Systems 6-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Dryer 6-34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alcohol Injector 6-34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Moisture Ejector 6-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alcohol Injector 6-34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alignment and Balance, Tire 6-51 . . . . . . . . . . . . . . . . . . . . . .
AM-FM Stereo 3-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM-FM Stereo with Remote Cassette Tape Player 3-10 . . . . .
Antenna 3-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Antifreeze 6-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Anti-Lock
Brakes 4-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake System Warning Light 2-61, 4-7 . . . . . . . . . . . . . . . .
Appearance Care 6-59 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appearance Care Materials 6-66 . . . . . . . . . . . . . . . . . . . . . . . Apply Park Brake Warning Light 2
-60 . . . . . . . . . . . . . . . . . .
Ashtray 2-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio Systems 3-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic Transmission Fluid 6-18 . . . . . . . . . . . . . . . . . . . . .
Automatic Transmission Shift Indicator Check 7-25 . . . . . . . .
Auxiliary Power Jacks 2-48 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Axle, Rear 6-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Airshift Control 2-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Differential Lock Control 2-41 . . . . . . . . . . . . . . . . . . . . . . .
Fluid Capacity 6-76 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shift Motor 6-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tw o-Speed Electric Shift Control 2-17 . . . . . . . . . . . . . . . .
Towing 5-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Battery 6-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Battery, Jump Starting 5-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake
Adjustment 6
-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Brake Systems 6-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Parking Brake 2-26 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electric/Hydraulic Parking Brake 2-25 . . . . . . . . . . . . . . . .
Electric/Hydraulic Parking Brake Fluid 6-36 . . . . . . . . . . . .
Exhaust 2-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid 6-30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9-7
New Vehicle ªBreak-Inº 2-5 . . . . . . . . . . . . . . . . . . . . . . . . .
Night Vision 4-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Noise Control System 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Odometer 2-53 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Off-Road Recovery 4-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil, Engine 6-13, 6-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Owner Checks and Services 7-23 . . . . . . . . . . . . . . . . . . . . . . .
Owner Publications Order Form 8-9 . . . . . . . . . . . . . . . . . . . .
Owner Publications, Ordering 8-8 . . . . . . . . . . . . . . . . . . . . . .
Paint Spotting, Chemical 6-65 . . . . . . . . . . . . . . . . . . . . . . . .
Parking
Brake 2
-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Check 7-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Indicator Light 2-60 . . . . . . . . . . . . . . . . . . . . . . . . . .
Over Things That Burn 2-29 . . . . . . . . . . . . . . . . . . . . . . . .
Passing 4-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power
Door Locks 2
-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option Fuses 6-69 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steering 4-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steering Fluid 6-28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Windows 2-31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Take-Off (PTO) 4-31 . . . . . . . . . . . . . . . . . . . . . . . . . .
Pregnancy, Use of Safety Belts 1-21 . . . . . . . . . . . . . . . . . . . .
Pressure Caps 6-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Problems on the Road 5-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Publications, Service and Owner 8-8 . . . . . . . . . . . . . . . . . . . .
Radiator 5-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radiator Pressure Cap 6-21 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radiator Shutters 2-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radio Reception 3-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Axle 6-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Airshift Control 2-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Differential Lock Control 2-41 . . . . . . . . . . . . . . . . . . . . . . .
Fluid Capacity 6-76 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shift Motor 6-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tw o-Speed Electric Shift Control 2-17 . . . . . . . . . . . . . . . .
Towing 5-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recovery Tank, Coolant 5-22 . . . . . . . . . . . . . . . . . . . . . . . . . .
Refrigerants, Air Conditioning 6-77 . . . . . . . . . . . . . . . . . . . .
Releasing Air Operated Parking Brake 5-15 . . . . . . . . . . . . . .
Remote Cassette Tape Player 3-10 . . . . . . . . . . . . . . . . . . . . . .
Replacement Wheels 6-57 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing Safety Belts 1-36 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reporting Safety Defects 8-6, 8-7 . . . . . . . . . . . . . . . . . . . . . .
Restraints
Checking 1
-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Child 1-26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Head 1-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing Parts After a Crash 1-36 . . . . . . . . . . . . . . . . . . .
System Check 7-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Right Passenger Position 1-21 . . . . . . . . . . . . . . . . . . . . . . . . .
Roadside Assistance 8-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rocking Your Vehicle 5-38 . . . . . . . . . . . . . . . . . . . . . . . . . . .
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