2003 GMC SIERRA DENALI warning

Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade.
If you don’t shift
down, you might have to use your brakes
so much that
they would get hot and no longer work well.
You can tow in DRIVE
(5). You may want to shift the
transmission to THIRD
(3) or, if necessary, a lower gear
selection
if the transmission shifts too often (e.g.,
under heavy loads and/or hilly conditions).
You may also want to activate the tow/haul mode
if the
transmission shifts too often. See “Tow/Haul Mode”
earlier in this section.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes.
If you turn your
engine
off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar
to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine
off. If you do get
the overheat warning, see
Engine Overheating on
page
5-27.
Parking on Hills
m
You really should not park your vehicle, with a
trailer attached, on a hill.
If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But
if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK
(P) yet.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P).
5. Release the regular brakes.
4-58

A. Engine Air CleanedFilter
B. Coolant Surge Tank
C. Air CleanerlFilter Restriction Indicator
B. Engine Oil Dipstick
E. Engine Oil Fill Cap
F. Automatic Transmission Dipstick
G. Fan
H. Remote Negative
(-) Terminal (GND)
I. Remote Positive (+) Terminal
J. Power Steering Fluid Reservoir
K. Brake Fluid Reservoir
L. Underhood Fuse Block
M. Battery
N. Windshield Washer Fluid Reservoir
Engine Oil
If the CHECK ENG 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 ENG
OIL LEVEL”
under
DIC Warnings and Messages on page 3-53.
You should check your engine oil level regularly; this is
an added reminder.
5-1 3

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

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

Checking Coolant
The coolant surge tank is
located in the engine
compartment on the
passenger’s side
of the
vehicle. See
Engine
Compartment Overview
on page
5-12 for more ’
Turning the surge tank pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. Never turn the surge tank pressure
cap
- even a little - when the engine and
radiator are hot. The
vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the
FULL COLD mark.
If the LOW COOLANT LEVEL message comes on and
stays on, it means you’re low on engine coolant.
See “Low Coolant Level” under
DIC Warnings and
Messages
on page 3-53.
Adding Coolant
If you need more coolant, add the proper DEX-COOL@
coolant mixture
at the surge tank, but only when the
engine is cool.
I
You can I: burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol,
and
it will burn if the engine parts are hot
enough. Don’t spill coolant
on a hot engine.
I I
When replacing the pressure cap, make sure it is
hand-tight.
5-26

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”
under
DIC Warnings and Messages on page 3-53.
If you get an engine overheat warning with no low
coolant message, but see or hear no steam, the problem
may not be too serious. Sometimes the engine can
get a little
too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. See “Driving on Grades” under
Towing a Trailer on page 4-51.
If you get the overheat warning with no sign of steam,
try this for a minute or
so:
1. If your air conditioner is on, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
3. If you’re in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
- AUTOMATIC OVERDRIVE (@ ).
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 andget
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.
5-29

Adding ~.ly p.-.n water to your coa....g system
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 i i water and DEX COOL@ coolant.
Notice: In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
I
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and
it will burn if the engine parts are hot
enough. Don’t spill coolant on a hot engine.
5-33