2003 GMC YUKON DENALI engine

Section 5 Service and Appearance Care
Service ............................................................ 5.3
Doing Your Own Service Work
......................... 5-3
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
............................... 5-6
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
Engine Oil ....................................... ..... 5.13
Engine Air Cleaner/Filter ............................. 5.17
Automatic Transmission Fluid ......................... 5-20
Engine Coolant ......................................... 5-22
Checking Things Under
~~
Coolant Surge Tank Pressure Cap ............... 5-25
Engine Overheating ....................................... 5-25
Cooling System ............................................ 5.28
Engine Fan Noise ......................................... 5.33
Power Steering Fluid
..................................... 5-34
Windshield Washer Fluid
................................ 5.34
Brakes
........................................................ 5.36
Battery
........................................................ 5-39
Jump Starting
............................................... 5.40
All-Wheel Drive .............................................. 5.46
Rear Axle .................................. .......... 5-48
Bulb Replacement .......................................... 5-49
Halogen Bulbs .............................................. 5-49
Headlamps
.................................................. 5-49
Running Lamps
......................................... 5-50
Center High-Mounted Stoplamp (CHMSL) ......... 5-52
Taillamps ..................................................... 5-52
Replacement Bulbs ................................... 5.53
Front Turn Signal, Sidemarker and Daytime
5- 1

Fuel
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.
Gasoline Specifications
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.
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 Indicator 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.
5-6
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.
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.

Checking Things Under
the
Hood
- .lings It burn can get c 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 located
inside the vehicle
to
the lower left of
the steering wheel.
5-1 0

Engine Compartment Overview
When you open the hood on the VORTECTM 6000 V8 engine you will see the following:
5-1 2

A. Engine Air CleanedFilter
B. Coolant Surge Tank
C. Air Filter Restriction Indicator
D. Engine Qii Dipstick
E. Engine Oil Fill
F. Automatic Transmission Dipstick
G. Fan
H. Remote Negative (-) Terminal (GND)
I. Remote Positive (+) Terminal
J. Power Steering Fluid Reservoir (Out of View)
K. Brake Master Cylinder Reservoir
L. Underhood Fuse Block
M. Battery
N. Windshield Washer Fluid Reservoir
Before closing the hood, be sure all filler caps are on
properly. Pull down the hood and close
it firmly.
Engine Oil
If the CHECK OIL LEVEL message appears on the
instrument cluster, it means you need to check
your engine oil level right away.
For more information, see “CHECK OIL LEVEL” under
DIC Warnings and Messages on page 3-52.
You should check your engine oil level regularly; this is
an added reminder.
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 loop handle and
is located in the engine
compartment 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 3

When to Add Engine Oil
If the oil is at or below the cross-hatched area at the tip
of the dipstick, 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 engine oil crankcase
capacity, see Capacities and Specifications on
page
5-96.
Notice: Don't add too much oil. If your engine has
so much oil that the oil level gets above the
cross-hatched area that shows the proper operating
range, your engine could be damaged.
The engine oil fill cap is
located on the valve cover
on the passenger's side
of the vehicle. See Engine
Compartment Overview
on page
5-12 for further
~ location information.
Be sure to
fill it enough to put the level somewhere in
the proper operating range. Push the dipstick all the way
back in when you're through.
5-1 4

What Kind of Engine Oil to Use
Oils recommended for your vehicle can be identified by
looking for the starburst symbol.
This symbol indicates that the oil has been certified by
the American Petroleum Institute (API).
Do not use
any oil which does not carry this starburst symbol.
1-1 If you choose to perform
i* Y
the engine oil change
service yourself, be sure
the oil you use has
the starburst symbol on
the front of the oil
container. If you have your
oil changed for you, be
sure the oil put into
your engine
is American
I I Petroleum Institute certified
for gasoline engines.
fou should also use the proper viscosity oil for your
vehicle, as shown in the viscosity chart.
RECOMMENDED SAE VISCOSITY GRADE ENGINE OILS
HOT
WEATHER
-
"F
5.100
+ 80
+ 60
t 40
t 20
0
f
-
"C
- +3e
- t 2i
- + 1t
- t4
- -7
- - 16

I
I
i
I-
/
COLD
WEATHER
DO NOT USE SAE 1OW-40, SAE 2OW-50 OR ANY OTHER VISCOSITY GRADE OIL NOT RECOMMENDED
5-1 5