Page 223 of 386
4-30
If you have a diesel engine, you may have to run it at a
higher speed to get enough heat. Then, shut the engine
off and close the window almost all the way to preserve
the heat. Start the engine again and repeat this only
when you feel really uncomfortable from the cold. But
do it as little as possible. Preserve the fuel as long as you
can. To help keep warm, you can get out of the vehicle
and do some fairly vigorous exercises every half hour or
so until help comes.Loading Your Vehicle
There is a GVW Rating label on your vehicle that shows
how much weight it may properly carry. It also shows
the size of your original tires and the inflation pressures
needed to obtain the gross weight capacity of your
vehicle. This is called the Gross Vehicle Weight
Rating (GVWR).
Page 255 of 386

6-
6-1
Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-4 Fuel (Gasoline Engine)
6
-5 Diesel Fuel Requirements and Fuel System
6
-15 Fuels in Foreign Countries (Gasoline Engines)
6
-15 Filling Your Tank
6
-17 Filling a Portable Fuel Container
6
-18 Checking Things Under the Hood
6
-20 Noise Control System
6
-21 Engine Oil (Gasoline Engines)
6
-27 Engine Oil (Caterpillar Diesel Engines)
6
-27 Engine Oil (DURAMAX Diesel)
6
-30 Engine Air Cleaner/Filter
6
-32 Automatic Transmission Fluid
6
-32 Manual Transmission Fluid
6
-34 Rear Axle
6
-34 Rear Axle Shift Motor (Option)
6
-35 Engine Coolant
6
-38 Engine Coolant (Caterpillar Diesel Engine)6
-38 Surge Tank Pressure Cap
6
-39 Power Steering Fluid
6
-40 Windshield Washer Fluid
6
-41 Brakes
6
-52 Battery
6
-54 Other Service Items
6
-58 Tires
6
-67 Appearance Care
6
-68 Cleaning the Inside of Your Vehicle
6
-71 Cleaning the Outside Your Vehicle
6
-75 GM Vehicle Care/Appearance Materials
6
-76 Vehicle Identification Number (VIN)
6
-76 Service Statement
6
-77 Service Parts Identification Label
6
-77 Electrical System
6
-86 Capacities and Specifications
6
-90 Normal Maintenance Replacement Parts
Page 264 of 386

6-10
To drain water, do the following:
1. Stop and park the vehicle in a safe place. Turn off
the engine and apply the parking brake.
2. Remove the fuel cap.
3. Place a fuel
-resistant container under the fuel filter.
The filter drain valve is located on the bottom of the
fuel filter. The fuel filter is located in the engine
compartment on the passenger's side of the vehicle,
or on the driver's side frame rail near the engine.
4. Open the drain valve by
turning two to three
turns. When fuel
empties from the valve,
all the water has been
drained. Close the valve
hand tight.5. Remove the fuel
-resistant container and properly
dispose of the contaminated fuel. To find out how to
properly dispose of contaminated diesel fuel, see
ªWhat to Do with Used Oilº in the ªEngine Oil
(Diesel Engines)º part, later in this section.
6. Install the fuel cap.
7. Start the engine and let it run for a few minutes.
If the engine stalls, the fuel system may need to be
primed. While draining the water from the fuel filter,
air may enter the fuel system. If air has entered the
fuel system the fuel system will need to be primed.
Refer to ªFuel Primingº later in this section.
If the water in fuel indicator comes on again after
driving a short distance or the engine runs rough or
stalls, a large amount of water has probably been
pumped into the fuel tank. The fuel tank should
be purged.
Fuel Priming
In order for the DURAMAX diesel engine fuel system
to work properly, the fuel lines must be full of fuel and
contain no air. If air gets into the fuel lines, it will be
necessary to prime the fuel lines to eliminate air before
operating the vehicle.
Page 270 of 386
6-16
C6/C7/C8 Models
CAUTION:
Fuel vapor is highly flammable. It burns
violently, and that can cause very bad injuries.
Don't smoke if you're near fuel or refueling your
vehicle. Keep sparks, flames and smoking
materials away from fuel.
The fuel cap can be on either or both sides of your
vehicle depending on option content.
To take off the cap, turn it slowly to the left
(counterclockwise).
CAUTION:
Gasoline Engine Vehicles: If you get gasoline on
you and then something ignites it, you could be
badly burned. Gasoline can spray out on you if
you open the fuel 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 ªhissº noise to stop. Then
unscrew the cap all the way.
When you put the cap back on, turn it to the right
(clockwise) until it is tight.
Page 271 of 386

6-17
NOTICE:
If you need a new fuel 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.
If you have dual tanks, fill the driver's side tank, or
forward tank, first. The fuel gage will give better
readings this way. Your gage will show the average level
of both tanks combined.
Filling a Portable Fuel Container
CAUTION:
Never fill a portable fuel container while it is in
your vehicle. Static electricity discharge from the
container can ignite the gasoline vapor. You can
be badly burned and your vehicle damaged if this
occurs. To help avoid injury to you and others:
Dispense gasoline only into approved
containers.
Do not fill a container while it is inside a
vehicle, in a vehicle's trunk, pickup bed or
on any surface other than the ground.
Bring the fill nozzle in contact with the
inside of the fill opening before operating
the nozzle. Contact should be maintained
until the filling is complete.
Don't smoke while pumping gasoline.
Page 340 of 386
6-86
Replacement Bulbs
It is recommended that you use an ACDelco type bulb whenever you need to replace one.
If you need a bulb replaced, contact your dealer.
Capacities and Specifications
Engine Specifications
Engine RPO LG5 L18 LG4 LB7
Engine Type 7.2L L6 8.1L V8 7.8L L6 6.6L V8
Fuel System HEUI SPFI Common Rail Common Rail
Firing Order
1
-5-3-6-2-41-8-7-2-6-5-4-31-5-3-6-2-41-2-7-8-4-5-6-3
Page 342 of 386

6-88 Engine Oil with Filter Capacity
Engine Quarts (Liters)
7.2L** 30.0 (28.4)*
8.1L** 6.5 (6.1)
7.8L** 23.8 (22.5 )
6.6L** 14.6 (13.8)
*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).
** Check fill level on the oil indicator after initial fill to
make sure it is actually full. Oil level may vary
depending on vehicle option content.
Fuel Tank Capacity
C4/C5 Models Gallons (Liters). . . . . . . . . . . . . . . . .
Standard* 41 (155.2). . . . . . . . . . . . . . . . . . . . . . . .
Optional 40 (151.4). . . . . . . . . . . . . . . . . . . . . . . . . .
Optional 60 (227.1). . . . . . . . . . . . . . . . . . . . . . . . . .
Optional 80 (302.8). . . . . . . . . . . . . . . . . . . . . . . . . .
C6/C7/C8 Models Gallons (Liters). . . . . . . . . . . . . .
Standard 50 (189.2). . . . . . . . . . . . . . . . . . . . . . . . .
Optional 35 (132.4). . . . . . . . . . . . . . . . . . . . . . . . . .
Optional 50 (189.2). . . . . . . . . . . . . . . . . . . . . . . . . .
Optional70 (264.8) . . . . . . . . . . . . . . . . . . . . . . . .
Optional75 (283.8) . . . . . . . . . . . . . . . . . . . . . . . .
Optional& 100 (378.5). . . . . . . . . . . . . . . . . . . . . . .
* One 25
-gallon (94.6 L) tank and one 16-gallon
(60.6 L) tank
Two 35
-gallon (132.4 L) tanks
One 25
-gallon (94.6 L) tank and One 50-gallon
(189.2 L) tank
&Two 50
-gallon (189.2 L) tanks
Page 346 of 386
6-92
Engine 7.2L 8.1L 7.8L 6.6L
Power Steering
Fluid FilterGM Part
No. 88892858GM Part
No. 88892858GM Part
No. 88892858GM Part
No. 88892858
Secondary
Fuel FilterCAT
1R0751GM Part
No. 25055052GM Part
No. 15098649
Pressure Caps
RC
-54GM Part
No. 15997145GM Part
No. 15075118GM Part
No. 15075118
*Optional Davco (K28) D350921 spin
-on type filter
located on driver's side frame rail.
**Optional Cold Weather (KUK) Racor B6484GM
spin
-on type filter located on driver's side frame rail.*** Optional air filter (GM Part No. 88937525)
for C6/C7/C8 Models. Fits inside standard size filter
(GM Part No. 88937548) listed previously.