2003 CHEVROLET TAHOE cooling

Hill and Mountain Roads
Driving on steep hills or mountains is different from
driving in ¯at or rolling terrain.
If you drive regularly in steep country, or if you're
planning to visit there, here are some tips that can make
your trips safer and more enjoyable. See
Off-Road
Driving with Your Four-Wheel-Drive Vehicle on
page 4-23
for information about driving off-road.
·Keep your vehicle in good shape. Check all ¯uid
levels and also the brakes, tires, cooling system
and transmission. These parts can work hard
on mountain roads.
·Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift to a lower gear when you go
down a steep or long hill.
{CAUTION:
If you do not shift down, your brakes could get
so hot that they would not work well. You
would then have poor braking or even none
going down a hill. You could crash. Shift down
to let your engine assist your brakes on a
steep downhill slope.
4-49

Trailer Brakes
If your trailer weighs more than 2,000 lbs. (900 kg)
loaded, then it needs its own brakes ± and they must be
adequate. Be sure to read and follow the instructions
for the trailer brakes so you'll be able to install,
adjust and maintain them properly.
If your vehicle is equipped with Stabilitrak
ž, your trailer
cannot tap into the vehicle's hydraulic brake system.
Your trailer brake system can tap into the vehicle's
hydraulic brake system only if:
·The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.
·The trailer's brake system will use less than
0.02 cubic inches (0.3 cc) of ¯uid from your vehicle's
master cylinder. Otherwise, both braking systems
won't work well. You could even lose your brakes.
If everything checks out this far, make the brake tap at
the port on the master cylinder that sends the ¯uid
to the rear brakes. But don't use copper tubing for this.
If you do, it will bend and ®nally break off. Use steel
brake tubing.
Driving with a Trailer
{CAUTION:
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon
monoxide (CO) could come into your vehicle.
You can't see or smell CO. It can cause
unconsciousness or death. See ªEngine
Exhaustº in the Index. To maximize your safety
when towing a trailer:
·Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
·Keep the rear-most windows closed.
·If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main heating
or cooling system on and with the fan on
any speed. This will bring fresh, outside air
into your vehicle. Do not use the climate
control setting for maximum air because it
only recirculates the air inside your vehicle.
See ªClimate Controlsº in the Index.
4-73

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
·start your engine,
·shift into a gear, and
·release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission ¯uid (don't over®ll),
engine oil, axle lubricant, belts, cooling system and brake
system. Each of these is covered in this manual, and the
Index will help you ®nd them quickly. If you're trailering,
it's a good idea to review these sections before you start
your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
Your vehicle is equipped with the following wiring
harnesses for towing a trailer.
4-77

Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside
of Your Vehicle...........................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-5
Gasoline Speci®cations....................................5-5
California Fuel...............................................5-6
Additives.......................................................5-6
Fuel E-85 (85% Ethanol).................................5-7
Fuels in Foreign Countries...............................5-8
Filling Your Tank............................................5-9
Filling a Portable Fuel Container.....................5-11
Checking Things Under
the Hood....................................................5-12
Hood Release..............................................5-12
Engine Compartment Overview.......................5-14
Engine Oil...................................................5-18
Engine Air Cleaner/Filter................................5-23
Automatic Transmission Fluid.........................5-26
Engine Coolant.............................................5-29
Coolant Surge Tank Pressure Cap..................5-32
Engine Overheating.......................................5-33Cooling System............................................5-36
Engine Fan Noise.........................................5-42
Power Steering Fluid.....................................5-43
Windshield Washer Fluid................................5-44
Brakes........................................................5-45
Battery........................................................5-48
Jump Starting...............................................5-49
All-Wheel Drive..............................................5-55
Rear Axle.......................................................5-56
Four-Wheel Drive............................................5-57
Front Axle......................................................5-58
Bulb Replacement..........................................5-59
Halogen Bulbs..............................................5-59
Headlamps..................................................5-60
Front Turn Signal, Sidemarker and Daytime
Running Lamps.........................................5-61
Side Identi®cation Marker Lamps.....................5-62
Roof Marker Lamps......................................5-62
Taillamps.....................................................5-64
Replacement Bulbs.......................................5-66
Windshield Wiper Blade Replacement..............5-66
Section 5 Service and Appearance Care
5-1

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-23.
B. Coolant Surge Tank. See
Cooling System on
page 5-36.
C. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-23.
D. Engine Oil Dipstick. See
Engine Oil on page 5-18.
E. Automatic Transmission Dipstick. See
Automatic
Transmission Fluid on page 5-26.
F. Engine Oil Fill. See
Engine Oil on page 5-18.
G. Fan. See
Cooling System on page 5-36.
H. Remote Negative (-) Terminal (GND). See
Jump
Starting on page 5-49.I. Power Steering Fluid Reservoir. See
Power Steering
Fluid on page 5-43.
J. Remote Positive (+) Terminal. See
Jump Starting on
page 5-49.
K. Brake Master Cylinder Reservoir. See
Brakes on
page 5-45.
L. Underhood Fuse Block. See
Fuses and Circuit
Breakers on page 5-109.
M. Battery. See
Battery on page 5-48.
N. Windshield Washer Fluid Reservoir. See
Windshield
Washer Fluid on page 5-44.
5-15

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-23.
B. Coolant Surge Tank. See
Cooling System on
page 5-36.
C. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-23.
D. Engine Oil Dipstick. See
Engine Oil on page 5-18.
E. Automatic Transmission Dipstick. See
Automatic
Transmission Fluid on page 5-26.
F. Engine Oil Fill. See
Engine Oil on page 5-18.
G. Fan. See
Cooling System on page 5-36.
H. Remote Negative (-) Terminal (GND). See
Jump
Starting on page 5-49.I. Remote Positive (+) Terminal. See
Jump Starting on
page 5-49.
J. Power Steering Fluid Reservoir. See
Power Steering
Fluid on page 5-43.
K. Brake Master Fluid Reservoir. See
Brakes on
page 5-45.
L. Underhood Fuse Block. See
Fuses and Circuit
Breakers on page 5-109.
M. Battery. See
Battery on page 5-48.
N. Windshield Washer Fluid Reservoir. See
Windshield
Washer Fluid on page 5-44.
5-17

How to Add Fluid
Refer to the Maintenance Schedule to determine what
kind of transmission ¯uid to use. SeePart D:
Recommended Fluids and Lubricants on page 6-18.
Add ¯uid only after checking the transmission ¯uid while
it is hot. (A cold check is used only as a reference.) If
the ¯uid level is low, add only enough of the proper ¯uid
to bring the level up to the HOT area for a hot check.
It doesn't take much ¯uid, generally less than one
pint (0.5 L).
Don't over®ll.
Notice:
We recommend you use only ¯uid labeled
DEXRONž-III, because ¯uid with that label is
made especially for your automatic transmission.
Damage caused by ¯uid other than DEXRON
ž-III is
not covered by your new vehicle warranty.
·After adding ¯uid, recheck the ¯uid level as
described under
How to Check.
·When the correct ¯uid level is obtained, push the
dipstick back in all the way; then ¯ip the handle
down to lock the dipstick in place.
Engine Coolant
The cooling system in your vehicle is ®lled with
DEX-COOLžengine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs ®rst, if you add only
DEX-COOL
žextended 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 5-33.
5-29

A 50/50 mixture of clean, drinkable water and
DEX-COOLžcoolant will:
·Give freezing protection down to-34ÉF (-37ÉC).
·Give boiling protection up to 265ÉF (129ÉC).
·Protect against rust and corrosion.
·Help keep the proper engine temperature.
·Let the warning lights and gages work as they
should.
Notice:When adding coolant, it is important that
you use only DEX-COOLž(silicate-free) coolant.
If coolant other than DEX-COOLžis added to
the system, premature engine, heater core or
radiator corrosion may result. In addition, the engine
coolant will require change sooner Ð at 30,000 miles
(50,000 km) or 24 months, whichever occurs ®rst.
Damage caused by the use of coolant other
than DEX-COOL
žis not covered by your new vehicle
warranty.
What to Use
Use a mixture of one-halfclean, drinkable waterand
one-half DEX-COOLžcoolant which won't damage
aluminum parts. If you use this coolant mixture,
you don't need to add anything else.
{CAUTION:
Adding only plain water to your cooling
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 would not get the overheat warning.
Your engine could catch ®re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
žcoolant.
5-30