2003 GMC YUKON DENALI service

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.
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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.

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

How to Reset the CHANGE ENGINE OIL
Message
The GM Oil Life System calculates when to change
your engine oil and filter based on vehic!e
use. Anytime
your oil is changed, reset the system
so it can
calculate when the next oil change is required.
If a
situation occurs where you change your
oil prior to a
CHANGE ENGINE OIL message being turned on, reset
the system.
To reset the CHANGE ENGINE
OIL message, see “GM
Oil Life System” under DIC Operation and Displays
on page 3-43 for vehicles equipped with the DIC, or do
the following:
1. Turn the ignition key to RUN with the engine off.
2. Fully press and release the accelerator pedal three
If the OIL LIFE RESET message flashes for
10 seconds,
the system is reset.
If the system does not reset, try the procedure once
again. If it still does not reset, see your dealer for
service. times
within five seconds.
What to Do with Used Oil
Used engine oil contains certain elements that may be
unhealthy for your skin and could even cause cancer.
Don’t let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good hand cleaner. Wash
or properly dispose of clothing or
rags containing used engine oil. See the manufacturer’s
warnings about the use and disposal of oil products.
Used oil can be a threat
to the environment. If you
change your own oil, be sure
to drain all the oil from the
filter before disposal. Never dispose of oil by putting it
in the trash, pouring it on the ground, into sewers, or into
streams or bodies of water. Instead, recycle it by
taking it to a place that collects used oil. If you have a
problem properly disposing of your used oil, ask
your dealer, a service station or a local recycling center
for help.
Engine Air Cleaner/Filter
The engine air cleanedfilter assembly has an air filter
restriction indicator that lets you know when the engine
air cleaner/filter is dirty and needs to be serviced.
The air filter restriction indicator is located on the air
filter assembly cover. See Engine Compartment
Overview
on page 5-72 for more information on location.
See Part
B: Owner Checks and Services on page 6-10
to determine when to check the air filter restriction
indicator.
5-1 7

The service window (A)
with the percentage scale shows the amount of
engine air cleaner/filter life used.
I I
When both service window (A) and service window (B)
turn orange, replace the engine air cleanedfilter.
After changing the engine air cleaner/filter, press the
button on top of the air filter restriction indicator
to
reset it. Your
engine air cleaner/filter is located in the air filter
housing near the front corner of the engine compartment
on the passenger’s side of the vehicle. See Engine
Compartment Overview
on page 5-12 for more
information on location.
5-1 8

I
1. To remove the engine air cleaner/filter, loosen the
screws on the cover.
2. Lift the cover upward and remove the engine air
cleaner/filter
out of the air cleaner housing. Care
should be taken to dislodge as little dirt as possible.
3. Clean the filter sealing surface and the housing.
4. Install the new engine air cleanedfilter. Refer
to the Maintenance Schedule to determine when
to replace the engine air cleanedfilter. See
Part 5:
Owner Checks and Services on page 6- 10.
Operating L.L engine _____. the air cleaner/filter
off can cause you or others to be burned. The
air cleaner not only cleans the air,
it stops
flame if the engine backfires.
If it isn’t there
and the engine backfires, you could be burned. Don’t drive with
it off, and be careful working
on the engine with the air cleanedfilter
off.
Notice: If the air cieaner/filter is off, a backfire can
cause a damaging engine fire. And, dirt can
easily get into your engine, which will damage
it.
Always have the air cleanedfilter in place when
you’re driving.
5. Install the cover and tighten the screws.
5-1 9

Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every
50,000 miles
(83
000 km) if the vehicle’s GVWR is over 8,600 or if
the vehicle is mainly driven under one or more of these
conditions:
In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
0 In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery
service.
If your vehicle’s GVWR is not over 8,600 and you do
not use your vehicle under any of these conditions,
change the fluid and filter every
100,000 miles
(1 66 000 km).
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice: Too much or too little fluid can damage
your transmission. Too much can mean that some of the fluid could come out and fall
on hot engine
part or exhaust system parts, starting a fire.
Too little fluid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level
if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic - especially in hot weather.
While pulling a trailer.
See
Part A: Scheduled Maintenance Services on
page 6-4.
5-20

If No Steam Is Coming From Your
Engine
An overheat warning, along with a low coolant message,
can indicate a serious problem. See
Low Coolant
Level Warning Message under DIC Warnings and
Messages
on page 3-52.
If you get an engine overheat warning but see or hear
no steam, the problem may not be
too serious.
Sometimes the engine can get a little
too hot when you:
0 Climb a long hill on a hot day.
Stop after high-speed driving.
0 Idle for long periods in traffic.
0 Tow a trailer. See Towing a Trailer on page 4-47.
If you get the overheat warning with no sign of steam, try
this for a minute or so:
1. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
If you no longer have the overheat warning, you can
drive. Just
to be safe, drive slower for about 10 minutes.
If the warning doesn’t come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there’s still no sign of steam, push down the
accelerator until the engine speed is about twice as fast
as normal idle speed for at least three minutes while
you’re parked. If you still have the warning, turn
off the
engine and get everyone out
of the vehicle until it
cools down. Also, see “Overheated Engine Protection
Operating Mode” listed previously in this section.
You may decide not
to lift the hood but to get service
help right away.
2. If you’re in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
- DRIVE (D).
5-27

Heater and rac.-:or hoses, and other engine
parts, can be very hot. Don’t touch them. If you
do, you can be burned.
Don’t run the engine
if there is a leak. If you
run
the engine, it could lose all coolant. That
could cause an engine fire, and you could be
burned. Get any leak fixed before you drive the
vehicle.
If there seems to be no leak, start the engine again.
The engine cooling fan speed should increase when idle
speed is doubled by pushing the accelerator pedal
down. If it doesn’t, your vehicle needs service. Turn
off
the engine.
Notice: Engine damage from running your engine
without coolant isn’t covered by your warranty.
See “Overheated Engine Protection Operating
Mode”
in the Index for information on driving to a
safe place
in an emergency.
Notice: When adding coolant, it is important that
you use only
DEX-COOL@ (silicate-free) coolant.
If coolant other than DEX-COOL@ is added to
the system, premature engine, heater core or radiator corrosion
may result. In addition, the engine
coolant will require change sooner
- at 30,000 miles
(50 000 km) or 24 months, whichever occurs first.
Damage caused by
the use of coolant other
than DEX-COOL@ is not covered by your new vehicle
warranty.
How to Add Coolant to the Coolant
Surge Tank
If you haven’t found a problem yet, check to see if
coolant is visible in the surge tank. If coolant is visible
but the coolant level isn’t at or above the
FULL
COLD mark, add a 50/50 mixture of clean, drinkable
water and
DEX-COOL@ coolant at the coolant
surge tank, but be sure the cooling system, including
the coolant surge tank pressure cap, is cool before you
do it. See Engine Coolant on
page 5-22 for more
information.
If no coolant is visible in the surge tank, add coolant as
follows:
5-29