2003 CHEVROLET C/K fuel

6-27
Engine Oil (Caterpillar

Diesel Engines)
See your Caterpillar
Operation & Maintenance Manual
for information on oil quality and viscosities as well as
the temperature range chart.
Engine Oil (DURAMAX Diesel)
Checking Engine Oil
It's a good idea to check your engine oil level every time
you get fuel.
The engine oil dipstick is
located in the engine
compartment on the driver's
side of the vehicle.
In order to get an accurate
reading, the oil must be
warm (at normal operating
temperature) and the vehicle
must be on level ground.Turn off the engine and give the oil at least five minutes
to drain back into the oil pan. With a cool engine, allow
30 minutes. If you don't, the oil dipstick might not show
the actual level.
Pull out the dipstick and clean it with a paper towel or a
cloth, then push it back in all the way. Remove it again,
keeping the tip down.

6-54
Other Service Items
Fuel Filter (Gasoline Engines)
The steel fuel filter is located near the engine
compartment on the driver's side of the vehicle.
See your Maintenance Schedule for recommended
service intervals.If your vehicle is equipped with the optional Davco
spin
-on type filter, it is located on the driver's side
frame rail.
Fuel Filter (Diesel Engines)
If you have a diesel engine, your fuel filter is located in
the engine compartment on the driver's side of the
vehicle, or along the driver's side frame rail. See ªFuel
Filter Replacementº earlier in this section for further
information.
Also see your Maintenance Schedule for recommended
service intervals.

6-55 Primary Fuel Filter and Water Separator
(If Equipped)
If you have a diesel engine,
you may have this spin
-on
filter. It is located on the
driver's side frame rail.
It has a clear plastic drain bowl at the bottom. Check the
drain bowl occasionally for any water or particles.
To drain the bowl, do the following:
1. Shut off the engine.
2. Partially open the drain valve at the bottom of
the filter.
See ªEngine Oilº in the Index for proper disposal
procedures.
Secondary Fuel Filter and Water
Separator/Heater (If Equipped)
If you have a Caterpillar

diesel engine, you may also
have this spin
-on filter and
fuel separator/heater. It will
be mounted in the engine
compartment on the driver's
side of the vehicle.
It has a metal drain bowl at the bottom. Occasionally,
check the bowl for any water or particles.
To check or drain the bowl, do the following:

Shut off the engine.

Push up on the spring loaded drain valve until clear
fuel is flowing from the valve.
The particles or water will drain out first. See ªEngine
Oilº in the Index for proper disposal procedures.

6-59 Inflation -- Tire Pressure
The GVW Rating label, which is on the driver's door,
shows the correct inflation pressures for your tires
when they're cold. ªColdº means your vehicle has
been sitting for at least three hours or driven no more
than 1 mile (1.6 km).
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

Tire overloading

Bad wear

Bad handling

Bad fuel economy
NOTICE: (Continued)
NOTICE: (Continued)
If your tires have too much air (overinflation),
you can get the following:

Unusual wear

Bad handling

Rough ride

Needless damage from road hazards

6-74
Finish Damage
Any stone chips, fractures or deep scratches in the finish
should be repaired right away. Bare metal will corrode
quickly and may develop into a major repair expense.
Minor chips and scratches can be repaired with touch
-up
materials available from your dealer or other service
outlets. Larger areas of finish damage can be corrected
in your dealer's body and paint shop.
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 vehicle washing system
can do this for you.

6-81
Fuse Usage
RH PARK LP Right
-hand Parking Lamps
LH PARK LP Left
-hand Parking Lamps
RADIO U Radio
PWR WINDOW Power Windows
BRAKE ISO Brake Warning Lamp
SPARE Spare Fuse
L
-RR TRUCK Left Rear Trailer Wiring
SPARE Spare Fuse
SPARE Spare Fuse
SPARE Spare Fuse
R
-RR TRUCK Right Rear Trailer Wiring
SPARE Spare FuseRelay Usage
BRAKE LAMP C4/C5 Brake Lamps, C6/C7/C8
Tractor/Trailer Wiring
IGN 4 Ignition
MARKER LP Sidemarker and Clearance Lamps
HTD FUEL LB7/LG4 Heated Fuel
AIR HTR LG4 Air Heater
ECU
MAINTAINLG4 Electronic Control Unit
DRL Daytime Running Lamps
CHMSL ISO Center High Mounted Stop Lamp
HTD MIRR Heated Mirrors
R-TRN TLR Right Trailer Turn Signal
L
-TRN TLR Left Trailer Turn Signal
SPARE Spare Relay
SPARE Spare Relay
SPARE Spare Relay

6-84
Primary Underhood Fuse Block
Relay Usage
NOTE 1 LG4 Powertrain Control Valve,
L18/LB7 Fuel Pump,
LG5 Heated Fuel
IGN B Ignition
STARTER StarterRelay Usage
HORN Horn
IGN A Ignition
PTO Power Take
-Off
REVERSE Reverse
NEUTRAL
STARTNeutral Start
Fuse Usage
RR DEFOG Rear Defog
ENG 1 Engine 1
ENG 3 Engine 3
PCM
-B Powertrain Control Module
BLANK Empty
ENG 4 Engine 4
ENG 2 Engine 2
HTD FUEL Heated Fuel
BLANK Empty
BLANK Empty

6-85
Fuse Usage
BLANK Empty
A/C COMP Air Conditioning Compressor
ABS 1 Anti
-Lock Brake System 1
ABS 2 Anti
-Lock Brake System 2
ABS 3 Anti
-Lock Brake System 3
ENGINE Engine
E/A PUMP Electronic/Automatic Pump
HORN Horn
NOTE 2 L18/LB7 Fuel, LG4 Powertrain
Control Valve, LG5 Electronic
Control Module
BLANK Empty
STUD A Spare
STUD B Spare
Secondary Underhood Fuse Block
Fuse Usage
IGN 1 Ignition 1
IGN 4 Ignition 4
IGN 3 Ignition 3
BATT/HAZ Battery/Hazard Warning Flashers
HEADLAMP Headlamps
LIGHTING Interior/Exterior Lamps
HVAC Comfort Control System
NOTE C4/C5 Electric Brake,
C6/C7/C8 Brake Lamps