GMC C-SERIES 1999 Owners Manual

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6-73
Name Circuits/Circuit Breakers
Protected
STP/HAZ
TURNStop Lamp, Turn Signal/Hazard
Lights, Fuel, Ignition Relay
(Gasoline Engines)
IGN SW3 Air Conditioner, Ignition Switch,
Axle, ChassisName Circuits/Circuit Breakers
Protected
INT/EXT
LIGHTSParking Lamps,
Dome/Panel Lights
HEAD LAMP Headlamps,
Daytime Running Lamps
AUX WRG Auxiliary, Park Brake
IGN SW1 Ignition Switch, Wash/Wipe,
Crank, Radio
HYD PUMP Hydraulic Brake,
Brake Pump Motor
HYD ABS EHCU
PWR
WDO/LCKSWindow, Door Locks
PARK BRK Parking Brake Motor
BLOWER
HORNBlower, Horn, Cigarette
Lighter/Auxiliary
FUEL/ENGINE Empty
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6-74
Replacement Bulbs
It is recommended that you use an AC
type bulb
whenever you need to replace one.
Before you replace any bulbs, be sure that all lamps are
off and the engine isn't running.
Capacities and Specifications
Replacement part numbers listed in this section are
based on the latest information available at the time of
printing. They are subject to later change. If a part listed
here isn't the same as the part in your vehicle when it
was built, or if you have any questions, please contact
your GM Truck dealer.
Engine Identification and Data
Engine RPO LG5 LP4/L21
Engine Type 7.2L L6 7.4L V8
Fuel System HEUI SPFI
Firing Order
1
-5-3-6-2-41-8-4-3-6-5-7-2
Wheel Nut Torque
Refer to ªTightening the Wheel Nutsº in this section for
wheel nut torque information.
Cooling System Capacity
Model Quarts (Liters)
7.2L 32.0 (30.0). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
with automatic transmission 30.0 (28.4). . . . . . . . . .
7.4L 25.0 (23.7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
with automatic transmission 23.0 (22.7). . . . . . . . . .
Above capacities (volumes) are approximate.
Crankcase Capacity
Capacities (volumes) shown are for normal refill. Add
oil as indicated when the oil filter element is changed.
Capacities given are approximate
-- keep level within
the operating range. Do not operate with fluid level
below the ADD line.
Engine
Capacity
-- Quarts (Liters)
7.2L 21 (19.0)*
7.4L 8 (7.5)
*Additional oil is required with auxiliary oil filter
systems. Make sure to add enough extra oil to fill the
auxiliary oil filter system. For vehicles equipped with
the LUBERFINER 750
-C, add 14 quarts (13.25 L).
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6-75
Extending the recommended oil change interval requires
the use of an infrared oil analysis program which shows
the condition of the oil and its additives. For more
information, consult your GM Truck dealer, who is an
authorized Caterpillar

engine dealer.
Transmission Capacity
Capacities (volumes) shown are approximate. For
manual transmissions, the correct oil level is to the
bottom of the fluid fill plug opening. The oil capacity
will vary, due to the angle of the transmission, with the
vehicle. For automatic transmissions, see the Allison
Automatic Transmission Operator's Manual for oil
check and maintenance information.
Manual Transmission Pints (Liters)
RT6609 12.0 (5.7). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RT6610 12.0 (5.8). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RTO6610 12.0 (5.8). . . . . . . . . . . . . . . . . . . . . . . . . . . RT6613 16.0 (7.5). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RT7608LL 19.5 (9.3). . . . . . . . . . . . . . . . . . . . . . . . . .
RT8609 15.0 (7.0). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FS4205A, FS4205B, FS4205C 12.5 (5.9). . . . . . . . . .
5205A, FS5205C 12.5 (5.9). . . . . . . . . . . . . . . . . . . . .
FS5306 18.0 (8.5). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FS6305A, FS6305B 19.0 (9.0). . . . . . . . . . . . . . . . . . .
FS6306 19.5 (9.2). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FS7206 20.0 (9.5). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
T8607B 36.0 (17.0). . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic Transmission Pints (Liters)
AT542 (for oil pan filter change) 30.0 (14.0)*. . . . . . .
AT545 (for oil pan filter change) 40.0 (19.0)*. . . . . . .
MT643 (for oil pan filter change) 13.0 (24.5)*. . . . . .
MT653 (for oil pan filter change) 36.0 (17.0)*. . . . . .
*Add two pints (one liter) when changing spin
-on filter.
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6-76 Rear Axle Lubricant Capacity
Single Speed Axle Lubricant, Pints (Liters)
15040S 21.0 (10.1). . . . . . . . . . . . . . . . . . . . . . . . . . . .
19060S 28.0 (12.8). . . . . . . . . . . . . . . . . . . . . . . . . . . .
21060D 28.0 (14.7). . . . . . . . . . . . . . . . . . . . . . . . . . . .
21060S 28.0 (14.7). . . . . . . . . . . . . . . . . . . . . . . . . . . .
22060S 28.0 (14.7). . . . . . . . . . . . . . . . . . . . . . . . . . . .
22080S 40.0 (20.3). . . . . . . . . . . . . . . . . . . . . . . . . . . .
23080S 40.0 (20.3). . . . . . . . . . . . . . . . . . . . . . . . . . . .
23431 40.0 (20.3). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23105S 48.0 (22.7). . . . . . . . . . . . . . . . . . . . . . . . . . . .
26085P 41.0 (19.5). . . . . . . . . . . . . . . . . . . . . . . . . . . .
26105S 48.0 (22.7). . . . . . . . . . . . . . . . . . . . . . . . . . . .
30105S 46.0 (23.2). . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tw o
-Speed Axle Lubricant, Pints (Liters)
15040T 24.0 (11.5). . . . . . . . . . . . . . . . . . . . . . . . . . . .
19060T 35.0 (17.5). . . . . . . . . . . . . . . . . . . . . . . . . . . .
21060T 35.0 (17.5). . . . . . . . . . . . . . . . . . . . . . . . . . . .
22060T 35.0 (17.5). . . . . . . . . . . . . . . . . . . . . . . . . . . .
23080T 39.0 (19.9). . . . . . . . . . . . . . . . . . . . . . . . . . . .
26080T 41.0 (19.5). . . . . . . . . . . . . . . . . . . . . . . . . . . .
Above capacities (volumes) are approximate.Tandem Axles Lubricant, Pints (Liters)
DS344 (front) 29.0 (15.1). . . . . . . . . . . . . . . . . . . . . . .
RS344 (rear) 28.0 (13.2). . . . . . . . . . . . . . . . . . . . . . . .
DS454 (front) 29.0 (15.1). . . . . . . . . . . . . . . . . . . . . . .
RS454 (rear) 28.0 (13.2). . . . . . . . . . . . . . . . . . . . . . . .
DS404, DS404P (front) 29.0 (15.1). . . . . . . . . . . . . . .
RS404 (rear) 34.0 (16.1). . . . . . . . . . . . . . . . . . . . . . . .
DT402P (front) 34.0 (16.1). . . . . . . . . . . . . . . . . . . . .
RT402 (rear) 34.0 (16.1). . . . . . . . . . . . . . . . . . . . . . . .
Above capacities (volumes) are approximate.
Fuel Tank Capacity
Model Gallons (Liters)
Standard 50 (189.0). . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional 35 (132.5). . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional 60 (227.1). . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional* 70 (264.0). . . . . . . . . . . . . . . . . . . . . . . . . .
Optional** 100 (378.0). . . . . . . . . . . . . . . . . . . . . . . .
* Two 35
-gallon (132 L) tanks
**Two 50
-gallon (189 L) tanks
Above capacities (volumes) are approximate.
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6-77
Air Conditioning Refrigerants
Not all air conditioning refrigerants are the same.
If the air conditioning system in your vehicle needs
refrigerant, be sure the proper refrigerant is used.
If you're not sure, ask your dealer.
Air Conditioning Refrigerant Capacity
Refrigerant R-134a 2.5 lbs. (1.134 kg). . . . . . . . . . . .
This capacity (volume) is approximate.
Normal Maintenance Replacement
Parts
Allison Transmission External Filters
Engine GM (AC) Part Number
7.2L 25011122 (PF897). . . . . . . . . . . . . . . . . . . . . . .
7.4L 25011122 (PF897). . . . . . . . . . . . . . . . . . . . . . .
Air Compressor Filter
Air Compressor GM Part Number
Bendix Tu
-Flo
550 (13.2 CFM)2467368
Service Replacement Part and
Filter Recommendations
Engine 7.2L 7.4L
RPO LG5 LP4/L21
Spark Plug Ð AC Type R41
-932
ÐGap Ð 0.060 inch
(1.52 mm)
ÐTorque Ð 22.0 lb. ft.
(30.0 Nm)
Oil Filter CAT

2P4004 AC Type PF-932
PCV Valve Ð AC Type CV
-774C
Air Cleaner* Donaldson
P522606Donaldson
P533355
Fuel Filter AC
-TP-915 Pri-
mary**AC Type GF-481
Pressure Caps RC
-54 Ð
*Optional Davco (K28) D350921 spin
-on type filter
located in component box.
**Optional Cold Weather (KUK) Racor B6484GM
spin
-on type located in component box. Optional Davco
heated fuel water separator mounted on the side of the
diesel engine.
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-NOTES
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7-
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Section 7 Scheduled Maintenance Services
This section covers the maintenance required for your vehicle. Your vehicle needs these services to retain its safety,
dependability and emission control performance.
7
-2 Introduction
7
-4 Part A: Scheduled Maintenance Services
7
-5 Scheduled Maintenance7
-23 Part B: Owner Checks and Services
7
-28 Part C: Recommended Fluids and Lubricants
7
-31 Part D: Maintenance Record
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7-2
Have you purchased the GM Protection Plan? The Plan
supplements your new vehicle warranties. See your
Warranty and Owner Assistance booklet, or your
GM dealer for details.
Introduction
Your Vehicle and the Environment
Proper vehicle maintenance not only helps to keep your
vehicle in good working condition, but also helps the
environment. All recommended maintenance procedures
are important. Improper vehicle maintenance can even
affect the quality of the air we breathe. Improper fluid
levels or the wrong tire inflation can increase the level
of emissions from your vehicle. To help protect our
environment, and to keep your vehicle in good
condition, please maintain your vehicle properly.
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7-3 How This Section is Organized
This maintenance schedule is divided into five parts:
ªPart A: Scheduled Maintenance Servicesº shows
what to have done and how often. Some of these
services can be complex, so unless you are technically
qualified and have the necessary equipment, you should
let your dealer's service department or another qualified
service center do these jobs.
CAUTION:
Performing maintenance work on a vehicle can
be dangerous. In trying to do some jobs, you can
be seriously injured. Do your own maintenance
work only if you have the required know
-how
and the proper tools and equipment for the job.
If you have any doubt, have a qualified
technician do the work.
If you are skilled enough to do some work on your
vehicle, you will probably want to get the service
information. See ªService and Owner Publicationsº in
the Index.ªPart B: Owner Checks and Servicesº tells you
what should be checked and when. It also explains what
you can easily do to help keep your vehicle in
good condition.
ªPart C: Recommended Fluids and Lubricantsº
lists some recommended products to help keep your
vehicle properly maintained. These products, or their
equivalents, should be used whether you do the work
yourself or have it done.
ªPart D: Maintenance Recordº provides a place
for you to record the maintenance performed on your
vehicle. Whenever any maintenance is performed, be
sure to write it down in this part. This will help you
determine when your next maintenance should be done.
In addition, it is a good idea to keep your maintenance
receipts. They may be needed to qualify your vehicle for
warranty repairs.
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7-4
Part A: Scheduled Maintenance
Services
Using Your Maintenance Schedule
We at General Motors want to help you keep your
vehicle in good working condition. But we don't know
exactly how you'll drive it. You may drive very short
distances only a few times a week. Or you may drive
long distances all the time in very hot, dusty weather.
You may use your vehicle in making deliveries or in
many other ways.
Because of all the different ways people use their
vehicles, maintenance needs vary. You may need more
frequent checks and replacements. So please read the
following and note how you drive. If you have any
questions on how to keep your vehicle in good
condition, see your GM dealer.
This part tells you the maintenance services you should
have done and when you should schedule them. If you
go to your dealer for your service needs, you'll know
that GM
-trained and supported service people will
perform the work using genuine GM parts.The proper fluids and lubricants to use are listed in Part C.
Make sure whoever services your vehicle uses these. All
parts should be replaced and all necessary repairs done
before you or anyone else drives the vehicle.
This schedule is for vehicles that:

carry passengers and cargo within recommended
limits. You will find these limits on your vehicle's
Certification/Tire label. See ªLoading Your Vehicleº
in the Index.

are driven on reasonable road surfaces within legal
driving limits.

use the recommended fuel. See ªFuelº in the Index.
Scheduled Maintenance Supplements
If your vehicle has a Caterpillar diesel engine, your
GM Owner's Manual is supplemented by the Caterpillar
Diesel Engine Operation & Maintenance Manual. If your
vehicle has an Allison transmission, your GM Owner's
Manual is supplemented by an Allison Transmission
Operator's Manual. Always refer to these manuals for
related maintenance services.
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