Page 284 of 436
Checking Things Under the Hood
I A CAUTION:
If your vehicle has air conditioning, the auxiliary
engine fan under the hood can
start up and
injure you even when the engine
is not running.
Keep hands, clothing and tools away from any
underhood electric
fan.
t -4
Things that burn can get on hot engine parts and
start a fire. These include liquids like gasoline or
diesel fuel, oil, coolant, brake fluid, windshield
washer and other fluids, and plastic or rubber. You or others could be burned. Be careful
not to drop or spill things that will burn onto
a hot engine.
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Refer to the Maintenance Schedule to determine when to
replace the air filter. See “Owner Checks and Services”
in
the Index.
Operating the engine with the
air cleaner off
can cause you OF 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
off.
I NOTICE:
If the air cleaner 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 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
50,000 miles
(83
000 km) if the vehicle’s CVWR is over 8,600 or
if the vehicle is mainly driven under one or more
of
these conditions:
In heavy city traffic where the outside temperature
regularly reaches
90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery service.
If your vehicle’s GVWR is not over
8,600 and you do
not use your vehicle under any
of these conditions, the
fluid and filter do
not require changing.
See “Scheduled Maintenance Services’’
in the Index.
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Page 331 of 436

Dual Tire Operation Buying New Tires
To find
out what kind and size of tires you need, look
at the CertificationEire label. When the vehicle is new, or whenever a wheel, wheel bolt
or wheel
nut is replaced, check the wheel nut torque after
100,
1,OOO and 6,000 miles (160, 1 600 and 10 OOO km)
of driving. For proper torque, see “Wheel Nut Torque” in
the Index.
The outer tire on a dual wheel setup generally wears faster
than
the inner tire. Your tires will wear more evenly and
last longer if you rotate the tires periodically.
If you’re
going to be doing a lot of driving on high-crown roads,
you can reduce tire wear by adding 5 psi (35 kPa) to the
tire pressure in the outer tires.
Be sure to return to the
recommended pressures when no longer driving under
those conditions. See “Changing a Flat Tire”
in the
Index for more information.
If you operate your vehicle with a tire that is badly
underinflated, the
tire can overheat. An overheated
tire
can lose air suddenly or catch fire. You or others
could be injured. Be sure all tires (including the
spare,
if any) are properly inflated.
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
“MS”
(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.
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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
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 aluminum
wheels, which can sometimes be repaired). See your
GM 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.
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Page 343 of 436

Underbody Maintenance
Chemicals used for ice and snow removal and dust
control can collect on the underbody. If these are not
removed, accelerated corrosion (rust) can occur on
the underbody parts such as fuel lines, frame, floor
pan and exhaust system
even though they have
corrosion protection.
At least every spring, flush these materials from the
underbody with plain water. Clean any areas where mud
and other debris can collect. Dirt packed in closed areas
of the frame should be loosened before being flushed.
Your dealer
or an underbody car washing system can
do this for you.
Chemical Paint Spotting
Some weather and atmospheric conditiow &n cr&ite a
chemical fallout. Airborne pollutants can fall upon and
attack painted surfaces on your vehicle. This damage
can take
two forms: blotchy, ringlet-shaped
discolorations, and small irregular dark spots etched
into the paint surface.
Although no defect in the paint job causes this,
GM will
repair, at no charge
to the owner, the surfaces of new
vehicles damaged by this fallout condition within
12 months or 12,000 miles
(20 000 km) of purchase,
whichever occurs first.
This applies only to materials manufactured and sold by
General Motors. Bodies, body conversions or equipment
not made or sold by General Motors are not covered.
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Page 350 of 436
Name
ECM-B
RR DEFOG IGN-E
Usage
Fuel Pump, PCMNCM
Rear Window Defogger
Auxiliary Fan Relay Coil,
A/C
Compressor Relay, Hot Fuel
Module, Dual Tanks
Name
FUEL SOL
GLOW PLUG
HORN
AUX FAN
ECM-
1
NC
ENG-
1
LIGHTING
BATT
IGN-A
IGN-B ABS
BLOWER STOP/HAZ
Usage
Fuel Solenoid (Diesel Engine)
Glow plugs (Diesel Engine)
Horn, Underhood Lamps
Auxiliary Fan
Injectors,
PCMNCM
Air Conditioning
lgnition Switch,
EGR, Canister
Purge,
EVRV Idle Coast Solenoid,
Heated
02, Fuel Heater
(Diesel Engine), Water Sensor
(Diesel Engine)
Headlamp and Panel Dimmer
Switch,
Fog and Courtesy Fuses
Battery, Fuse Block Busbar
Ignition Switch
Ignition Switch
Anti-Lock Brake Module
Hi Blower Relay
Stoplamps
6-74
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Page 354 of 436

Fuel Tank Capacity (Approximate)
Type
Short Bed
Long Bed Standard Crew Cab
Chassis-Cab Side Tank
Chassis-Cab Rear Tank 3500
HD Models Side Tank
3500
HD Models Rear Tank
Cooling System Capacity (Approximate)
After refill, the level must be rechecked. See “Cooling
System” in the Index.
Engine
“VORTEC” 4300
“VORTEC”
5000
“VORTEC” 5700
“VORTEC” 7400
“VORTEC”
7400
w/3500 HD
VIN
W
M
R
J
J
Quantity
13 quarts (12.3 L)
17.5 quarts (16.6 L)
17.5 quarts (16.6 L)
25 quarts (23.5 L)
28.5 quarts (27 L)
Crankcase Capacity (Approximate)
After refill, the level must be rechecked. See “Engine
Oil” in the Index.
Engine
“VORTEC” 4300
“VORTEC”
5000
“VORTEC” 5700”
“VORTEC” 7400*
VIN
W
M
R
J
Quantity with Filter?
5 quarts (4.8 L)
5 quarts (4.8 L)
7 quarts (6.5 L)
4.5 quarts (4.3
L)
?Oil
filter should be changed at every oil change.
*Add one additional quart (.946
L) for C-3500 HD Models.
Quantity
26 gallons (98 L)
34 gallons (128 L)
34 gallons (128 L)
22 gallons (83 L)
18 gallons (68 L)
22 gallons (83 L)
18 gallons (68 L)
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 GM dealer.
See the refrigerant charge label under the hood for
information regarding refrigerant capacity.
6-78
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Page 356 of 436
Introduction
IMPORTANT:
KEEP ENGINE OIL
AT THE PROPER
LEVEL AND CHANGE AS
RECOMMENDED
I
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.
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.
7-2
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