Page 283 of 436
/1 CAUTION:
If you get gasoline on yourself and then
something ignites it, you could be badly burned. Gasoline can spray out on you if you open the
fuel filler cap too quickly. This spray can happen
if your tank is nearly full, and
is more likely in
hot weather. Open the fuel filler cap slowly and
wait for
any “hiss” noise to stop. Then unscrew
the cap all the
way.
When you put the cap back on, turn it to the right
(clockwise)
until you hear a clicking sound. Make sure
you fully install the cap.
NOTICE:
If you need a new cap, be sure to get the right
type.
Your dealer can get one for you. If you get
the wrong type, it may not
fit or have proper
venting, and your fuel tank and emissions system
might be damaged.
Be careful not
to spill gasoline. Clean gasoline from
painted surfaces as soon as possible. See “Cleaning the
Outside of Your Vehicle” in the Index.
6-7
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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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Page 291 of 436

Engine Oil (Gasoline Engine)
If your vehicle has a diesel engine, see “Engine Oil (Diesel Engine)” in the Diesel Engine Supplement.
It’s a good idea to check your engine oil every time you
get fuel. In order to get an accurate reading, the oil must
be warm and the vehicle must be on level ground.
The engine oil dipstick has
a yellow ring handle and is
located on the passenger’s side
of the engine.
Turn
off the engine and give the oil a few minutes to
drain back into the oil pan.
If you don’t, the oil dipstick
might not show the actual level.
Checking Engine Oil
Pull out the dipstick and clean it with a paper towel or
cloth, then push it back in all the way. Remove it again,
keeping the tip down, and check the level.
When to Add Oil
If the oil is at or below the ADD mark, then you’ll need
to add at least one
quart of oil. But you must use the
right kind. This part explains what kind of oil to use.
For
crankcase capacity, see “Capacities and Specifications”
in the Index.
6-15
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Page 293 of 436

RECOMMENDED SAE YlSCOSlTT GRADE ENGINE OILS I
FOR BEST FUEL ECONOMY AND COLD STARTING, SELECT THE LOWEST
SAL VISCOSITY GRADE OIL
FOR THE EXPECTED TEMPERATURE RANGE. I
HOT
WEATHER
COLD
WEATHER
SAE 5w-30 PREFERRED
LWK
Fm THIS
SYMBOL
DO NOT USE SAE 2ow-50 OR ANY OTHER GRADE OIL NOT RECOMMENDED
As shown in the chart, SAE 5W-30 is best for your
vehicle. However, you can use
SAE 1OW-30 if it’s going
to be
0°F (- 18°C) or above. These numbers on an oil
container
show its viscosity, or thickness. Do not use
other viscosity oils, such
as SAE 20W-50.
NOTICE:
Use only engine oil with the American Petroleum
Institute Certified For Gasoline Engines
“Starburst” symbol. Failure to use the
recommended oil can result in engine damage
not covered by your warranty.
GM Goodwrench@ oil meets all the requirements for
your vehicle.
If you are in an area where the temperature falls below
-20°F (-29”C), consider using either an SAE 5W-30
synthetic oil or an SAE OW-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
6-17
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Page 327 of 436

Inflation -- Tire Pressure
The Certificationmire label, which is on the rear edge of
the driver’s door, or on the incomplete vehicle document
in the cab, shows the correct inflation pressures for your
tires when they’re cold. “Cold” means your vehicle has
been sitting for at least three hours or driven no more
than
1 mile (1.6 km).
You can operate some vehicles at reduced inflation
pressures only when you’ll be carrying reduced loads.
On those vehicles, the minimum cold inflation pressures
for
a typical reduced load are printed on the Improved
Ride Tire Pressure label located on the driver’s door.
Weigh the vehicle to find the load on each tire and see
the label for the minimum cold inflation pressures for
that load.
NOTICE:
Don’t let anyone tell you that underinflation or
overinflation is all right.
It’s not. If your tires
don’t have enough air (underinflation), you can
get the following:
Too much flexing
Too much heat
0 Tire overloading
Bad wear
Bad handling
Bad fuel economy.
If your tires have too much air (overinflation),
you can get the following:
Unusual wear
Bad handling
Rough ride
Needless damage from road hazards.
6-51
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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 353 of 436

Normal Maintenance Replacement Parts
Replacement part numbers listed in this section are based on the latest information available at the time of printing,
and are subject to change. If a part listed
in this manual is not the same as the part used in your vehicle when it was
built, or if you have any questions, please contact your GM truck dealer.
These specifications are for information only. If you have any questions, see the service manual for the chassis or
refer to the body manufacturer's publications.
VIN Code
Oil Filter*
Air Cleaner Filter*
PCV Valve*
Spark Plugs*
Fuel Filter* Wiper Blades**
Wiper Blade Type
Wiper Blade Length
W
PF52
A
1 300C
CV746C
4 1-932
GF626
22 154886
Trico 18 inches (45.0 cm)
M
PF1218T
A 1300C
CV796C
41 -932 GF626
22154886
Trico
18 inches (45.0 cm)
*AC part number
**GM part number
?Use a PF52 oil filter if your vehicle has four-wheel drive.
R
PF1218T
A 1300C
CV796C
4 1-932
GF626
22154886
Trico 18 inches (45.0 cm)
J
PF1218
A 1300C
cv774c
4 1-932
GF626
22154886
Trico
18 inches (45.0 cm)
6-77
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