2003 GMC SIERRA DENALI engine oil

When to Add Engine Oil
If the oil is at or below the cross-hatched area at the dip
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- 104.
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.
71 located on the passenger’s
The
engine oil
fill cap is
side valve cover.
See
Engine Comparfment Overview on page 5-12 for
more information on location.
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 5

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.
If you choose to perform
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 Petroleum
Institute certified for
gasoline engines.
You should also use the proper viscosity oil for your
vehicle, as shown in the viscosity chart.
I RECOMMENDED SAE VISCOSITI 6RADE ENGINE OILS I
HOT
WEATHER
/7 "F OC'
+loo- - +38
+BO--+27
i.60--+16
+40- - +4
t20 - - -7
0---18 I
COLD
WEATHER
LOOK
FOR MIS j
SYMBOL '
ACCEPTABLE r IF 5W-30 IS NOT -30 AVAILABLE
RECOMMENDED
DO NOT USE SAE
IOW-40, SAE 20W-50 OR ANY OTHER
MSCOSIWGRADE OIL NOT RECOMMENDED
5-1 6

As in the chart shown previously, SAE 5W-30 is the
only viscosity grade recommended for your vehicle.
You should look for and use only oils which have the
API Starburst symbol and which are also identified
as SAE 5W-30. If you cannot find such SAE 5W-30 oils,
you can use an SAE IOW-30 oil which has the API
Starburst symbol,
if it's going to be 0°F (-18°C)
or above. Do not use other viscosity grade oils, such as
SAE 1OW-40 or SAE 20W-50 under any conditions.
Notice: Use only engine oil with the American
Petroleum Institute Certified For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.
GM Goodwrench@ oil meets all the requirements for
your vehicle.
If you are in an area of extreme cold, where the
temperature falls below -20°F
(-29"C), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE OW-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely
low temperatures.
Engine Oil Additives
Don't add anything to your oil. The recommended oils
with the starburst symbol are all you will need for
good performance and engine protection.
When to Change Engine Oil
(GM Oil Life SystemTM)
Your vehicle has a computer system that lets you know
when to change the engine
oil and filter. This is based on
engine revolutions and engine temperature, and not on
mileage. Based on driving conditions, the mileage
at which an oil change will be indicated can vary
considerably. For the oil life system to work properly,
you must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is necessary.
A CHANGE ENGINE
OIL SOON message will come on.
Change your oil as soon as possible within the next two
times you stop for fuel. It is possible that,
if you are driving
under the best conditions, the oil life system may not
indicate that an oil change is necessary for over a year.
However, your engine oil and filter must be changed at
least once a year and at this time the system must be
reset. It is also important to check your oil regularly and
keep it at the proper level.
If the system is ever reset accidentally, you must
change your oil at 3,000 miles (5
000 km) since your
last oil change. Remember to reset the oil life system
whenever the oil is changed.
5-1 7

How to Reset the CHANGE ENGINE OIL
Message
The GM Oil Life SystemTM calculates when to change
your engine oil and filter based on vehicle 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 can change your oil prior to
a CHANGE ENGINE
OIL message being turned on,
reset the system.
To reset the CHANGE ENGINE OIL message,
do the
following:
1. Turn the ignition key to RUN with the engine off.
2. Fully press and release the accelerator pedal three
times within five seconds.
If the CHANGE ENGINE OIL message flashes for five
seconds, the system is reset. If the system will not reset,
try the procedure again.
If the system still does not
reset, see your dealer for service.
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.
5-1 8

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 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.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery
If you do not use your vehicle under any of these
conditions, change the fluid and filter every
100,000 miles (1 66 000 km).
See
Part A: Scheduled Maintenance Services on
page
6-4.
service.
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:
0 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.
To get the right reading, the fluid should be at normal
operating temperature, which is 180°F
to 200°F
(82°C to 93°C).
5-2
1

Engine Coolant
The cooling system in your vehicle is filled with
DEX-COOL@ engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240
000 km), whichever occurs first, if you add only
DEX-COOL@ extended life coolant.
The following explains your cooling system and how to
add coolant when
it is low. If you have a problem
with engine overheating, see
Engine Overheating on
page
5-27.
A 50/50 mixture of clean, drinkable water and
DEX-COOL@ coolant will:
Give freezing protection down to -34°F ( -37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
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.
Let the warning lights and gages work as they
should.
5-24

What to Use
Use a mixture of one-half dean, drinkable water and
one-half
DEX-COOL@ coolant which won’t damage
aluminum parts.
If you use this coolant mixture,
vou don’t need
to add anvthing else.
I
Addir - mi- -)lain water to lr cooling s- tem
can be dangerous. Plain water, or some other
liquid such as alcohol, can boil before the
proper coolant mixture will. Your vehicle’s
coolant warning system
is set for the proper
coolant mixture.
With plain water or the wrong
mixture, your engine could get too hot
but you
wouldn’t get the overheat warning. Your engine could catch fire and you or others could be burned. Use a
50/50 mixture of clean, drinkable
water and
DEX-COOL@ coolant.
Notice: If you use an improper coolant mixture,
your engine could overheat and be badly damaged.
The repair cost wouldn’t be covered by your
warranty. Too much water
in the mixture can freeze
and crack the engine, radiator, heater core
and
other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
Notice: If you use the proper coolant, you don’t
have to add extra inhibitors or additives which claim
to improve the system. These can be harmful.
5-25

Coolant Surge Tank Pressure Cap
The coolant surge tank
pressure cap must be fully
installed on the coolant
surge tank.
Nofice: Your pressure cap is a pressure-type cap
and must be tightly installed to prevent coolant loss
and possible engine damage from overheating. See “Capacities and Specifications” for more
information.
Engine Overheating
You will find a coolant temperature gage on your
vehicle’s instrument panel. See
Engine Coolant
Temperature Gage
on page 3-36. In addition, you will
find a LOW COOLANT, ENGINE OVERHEATED and a
REDUCED ENGINE POWER message in the DIC on
the instrument panel. See
Driver lnformation Center
(DIC)
on page 3-43.
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates firing groups
of cylinders helps prevent engine damage. In this mode,
you will notice a
loss in power and engine performance.
This operating mode allows your vehicle to be driven to
a
safe place in an emergency. Driving extended miles (km)
and/or towing a trailer in the overheat protection mode
should be avoided.
Nofice: After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant
loss, change the oil and reset the oil
life system. See “Engine
Oil” in the Index.
5-27