fuel GMC SIERRA DENALI 2003 Owner's Manual

Towing a Trailer
If you don’t ,se the correct eq-., ...__. t and
drive properly, you can lose control when you
pull a trailer. For example,
if the trailer is too
heavy, the brakes may not work well
-- or even
at all. You and your passengers could be
seriously injured.
Pull a trailer only if you have
followed all the steps in this section.
Ask your
dealer for advice and information about towing
a trailer with your vehicle.
Notice: Pulling a trailer improperly can damage
your vehicle and result in costly repairs not covered
by your warranty.
To pull a trailer correctly, follow
the advice in this part, and see your dealer for
important information about towing a trailer with
your vehicle. Additional rear axle maintenance is required for a vehicle used to tow a trailer. See
“Scheduled Maintenance Services” in the Index.
To identify the vehicle trailering capacity of your vehicle,
you should read the information in “Weight of the
Trailer” that appears later in this section.
If yours was built with trailering options, as many are,
it’s ready for heavier trailers. But trailering is different
than just driving your vehicle by itself. Trailering means
changes in handling, durability and fuel economy.
Successful, safe trailering takes correct equipment, and it has to be used properly.
That’s the reason for this part. In it are many time-tested,
important trailering tips and safety rules. Many of
these are important for your safety and that of your
passengers.
So please read this section carefully before
you pull a trailer.
If You Do Decide To Pull A Trailer
If you do, here are some important points:
e
There are many different laws, including speed limit
restrictions, having to do with trailering. Make sure
your rig will be legal, not only where you live
but also where you’ll be driving.
A good source for
this information can be state or provincial police.
Consider using a sway control
if your trailer will
weigh
5,000 Ibs. (2 270 kg) or less. You should
always use a sway control
if your trailer will weigh
more than
5,000 Ibs. (2 270 kg). You can ask a
hitch dealer about sway controls.
Don’t tow a trailer at all during the first
500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
4-5 1

Tow/haul is designed to be most effective when the
vehicle and trailer combined weight is at least
75 percent
of the vehicle’s Gross Combined Weight Rating
(GCWR). See Weight of the Trailer later in this section.
Tow/haul
is most useful under the following driving
conditions:
When pulling a heavy trailer or a large or heavy
When pulling a heavy trailer or a large or heavy
load
through rolling terrain.
load in stop and go traffic.
When pulling a heavy trailer or a large or heavy
load in busy parking lots where improved low
speed control of the vehicle is desired.
Operating the vehicle in tow/haul when lightly loaded or
with no trailer at all will not cause damage. However,
there is no benefit to the selection of tow/haul when the
vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission driving
characteristics and reduced fuel economy. Tow/haul
is recommended only when pulling a heavy trailer or a
large or heavy load.
Weight of the Trailer
How heavy can a trailer safely be?
It depends
on how you plan to use your rig. For
example, speed, altitude, road grades, outside
temperature and how much your vehicle is used to pull
a trailer are all important. And, it can also depend
on any special equipment that you have on your vehicle.
Use one of the following charts to determine how
much your vehicle can weigh, based upon your vehicle
model and options.
Maximum trailer weight is calculated assuming only the
driver is in the tow vehicle and it has all the required
trailering equipment. The weight
of additional optional
equipment, passengers and cargo in the tow vehicle
must be subtracted from the maximum trailer weight.
4-53

Section 5 Service and Appearance Care
Service ............................................................ 5.3
Doing Your Own Service Work
......................... 5-4
Adding Equipment to the Outside
of Your Vehicle
........................................... 5-4
Fuel
................................................................ 5.5
Gasoline Octane
............................................ 5.5
Gasoline Specifications
.................................... 5.5
California Fuel
............................................... 5.6
Additives
....................................................... 5.6
Fuels in Foreign Countries
................. ....... 5.7
Filling Your Tank
......................................... 5-7
Filling a Portable Fuel Container
.................... 5-9
the Hood
............................................. 5.10
Hood Release
........................................ ,.5-10
Engine Compartment Overview
....................... 5.12
Checking
Things Under
Engine Oil
................................................... 5.13
Engine Air Cleaner/Filter
................................ 5.19
Engine Coolant
............................................. 5.24
Engine Overheating
....................................... 5.27
Cooling System
............................................ 5.30
Automatic
Transmission Fluid
........................ -5-21
Coolant Surge Tank Pressure Cap
.................. 5-27 Engine
Fan Noise
......................................... 5.36
Power Steering Fluid
..................................... 5.37
Windshield Washer Fluid
................................ 5-38
Brakes
........................................................ 5.39
Battery
........................................................ 5.42
Jump Starting
............................................... 5.43
All-Wheel Drive
......................... .............. 5-49
Rear Axle
....................................................... 5-50
Front Axle
...................................................... 5-51
Bulb Replacement
.......................................... 5-52
Halogen Bulbs
.............................................. 5-52
Headlamps
................................................. -5-52
Roof Marker Lamps
...................................... 5-54
Cargo Lamp
............................................. 5-56
Taillamps
..................................................... 5-58
Replacement Bulbs
....................................... 5-59
Front
Turn Signal, Sidemarker
and Daytime
Running Lamps
......................................... 5-53
Center High-Mounted Stoplamp (CHMSL) and
Pickup
Box Identification and Fender Marker
Lamps
..................................................... 5-58
Windshield Wiper Blade Replacement
.............. 5-60
5-
1

Fuel Gasoline Specifications
Use of the recommended fuel is an important part of the
proper maintenance of your vehicle.
Gasoline Octane
Use regular unleaded gasoline with a posted octane
of
87 or higher. If the octane is less than 87, you may
get a heavy knocking noise when you drive.
If this
occurs, use a gasoline rated at
87 octane or higher as
soon as possible. Otherwise, you might damage
your engine. A little pinging noise when you accelerate
or drive uphill is considered normal. This does not
indicate a problem exists or that a higher-octane fuel is
necessary. If you are using
87 octane or higher-octane
fuel and hear heavy knocking, your engine needs
service. It
is recommended that gasoline meet specifications
which were developed by the American Automobile
Manufacturers Association and endorsed by the
Canadian Vehicle Manufacturers Association for better
vehicle performance and engine protection. Gasoline
meeting these specifications could provide improved
driveability and emission control system performance
compared to other gasoline.
In Canada,
look for the
“Auto Makers’ Choice” label
on the pump.
I I
Canada Only
5-5

California Fuel
If your vehicle is certified to meet California Emission
Standards (see the underhood emission control label),
it is designed to operate on fuels that meet California
specifications. If this fuel is not available
in states
adopting California emissions standards, your vehicle
will operate satisfactorily on fuels meeting federal
specifications, but emission control system performance
may be affected. The malfunction indicator lamp may
turn on (see
Malfunction lndicator Lamp on page 3-38 )
and your vehicle may fail a smog-check test. If this
occurs, return
to your authorized GM dealer for
diagnosis. If it is determined that the condition is caused
by the type of fuel used, repairs may not be covered
by your warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work properly.
You should not have
to add anything to your fuel. Gasolines containing
oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area to contribute
to clean air. General Motors
recommends that you use these gasolines, particularly
if
they comply with the specifications described earlier.
Notice: Your vehicle was not designed for fuel
that contains methanol. Don’t use fuel containing
methanol.
It can corrode metal parts in your
fuel system and also damage the plastic and rubber
parts. That damage wouldn’t be covered under
your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors does
not recommend the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs and
the performance of the emission control system may
be affected. The malfunction indicator lamp may turn on.
If this occurs, return to your authorized GM dealer
for service.
5-6

Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard
to
find. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel wouldn’t be
covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major
oil company that does business in the
country where you’ll be driving.
Filling Your Tank
Fuel va,_ r is hi,---, 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.
5-7

While refueling, hang the fuel cap by the tether using
the hook located on the inside of the filler door.
To remove the fuel cap, turn it slowly to the left
(counterclockwise).
- -
If you get fuel on yourself and then something
ignites
it, you could be badly burned. Fuel 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 cap slowly and wait for any
“hiss” noise to stop. Then unscrew the cap all
the way.
Be careful not to spill fuel. Clean fuel from painted
surfaces as
soon as possible. See Cleaning the Outside
of Your Vehicle on page 5-88.
5-8

When you put the fuel cap back on, turn it to the right
(clockwise) until you hear a clicking sound. Make
sure you fully install the cap. The diagnostic system can
determine
if the fuel cap has been left off or improperly
installed. this would allow fuel
to evaporate into the
atmosphere. See
Malfunction Indicator lamp on
page 3-38.
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 properly.
This may cause your malfunction indicator lamp to
light and may damage your fuel tank and emissions
system. See “Malfunction Indicator Lamp” in the
Index.
Filling a Portable Fue ‘~er
Never fill -)ortable 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:
0 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.
0 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.
5-9

Checking Things Under
1-eH
od
Things ti.-- burn c2.. get on hot engine parts
and start a fire. These include liquids like 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.
Hood Release
To open the hood do the following:
1. Pull the handle inside
the vehicle located
under and to the left
of
the steering wheel.
5-1 0

Checking Engine Oil
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 looped handle
and is located on the
passenger’s side of the
vehicle. See
Engine
Compartment
Overview
on page 5- 12 for more
information on location. Turn
off the
engine and give the oil several minutes to
drain back into the oil pan.
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
cloth, then push it back in all the way. Remove it again,
keeping the tip down, and check the level.
5-1 4