2003 PONTIAC GRAND PRIX overheating

Engine Coolant Temperature
Warning Light
TEMP
This light tells goti ihai
the engine coolant has
overheated or the
radiator cooling fan is
not working.
If you have been operating the vehicle under normal
driving conditions, you should pull
of the road, stop the
vehicle and turn
off the engine as soon as possible.
See Engine Overheating on page
5-33.
Engine Coolant Temperature Gage
United States
19
Canada
Your vehicle has a gage that shows the engine coolant
temperature.
If the gage pointer moves into the
shaded area, the engine is too hot.
That reading means the same thing as the warning
light. It means that the engine coolant has overheated.
If you have been operating the vehicle under normal
conditions, you should pull
off the road, stop the vehicle,
and turn
off the engine as soon as possible.
See Engine Overheating
on page 5-33.
3-31

Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle may need a
different turn signal flasher and/or extra wiring. Check
with your dealer. The arrows on your instrument
panel will flash whenever you signal a turn or lane
change. Properly hooked up, the trailer lamps will also
flash, telling other drivers you’re about to turn,
change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will flash for turns even
if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It’s
important to check occasionally to be sure the trailer
bulbs are still working.
Your vehicle has bulb warning lights. When you plug a
trailer lighting system into your vehicle’s lighting
system, its bulb warning lights may not let you know
if
one of your lamps goes out. So, when you have a trailer
lighting system plugged in, be sure to check your
vehicle and trailer lamps from time to time to be sure
they’re all working. Once you disconnect the trailer
lamps, the bulb warning lights again can tell you
if one
of your vehicle lamps is out.
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.
On a long uphill grade, shift down and reduce your
speed to around
45 mph (70 km/h) to reduce the
possibility of engine and transaxle overheating.
If you have overdrive, you may have to drive in
THIRD (3) instead of AUTOMATIC OVERDRIVE (D).
Parking on Hills
1 -J really should not ,,rk yo^, wG,kle, 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.
4-42

But if you ever have to park your rig on a hill, here’s
how to do it:
1.
2.
3.
4.
5.
Apply your regular brakes, but don’t shift into
PARK
(P) yet.
Have someone place chocks under the trailer
wheels.
When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
Reapply the regular brakes. Then apply your
parking brake, and then shift to PARK
(P).
Release the regular brakes.
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,
0 shift into a gear, and
0 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 Part
A: Scheduled Maintenance
Services on page
6-4 for more information. Things that
are especially important in trailer operation are
automatic transaxle fluid (don’t overfill), engine oil, drive
belts, cooling system and brake system. Each of
these is covered in this manual, and the Index will help
you find them quickly.
If you’re trailering, it’s a good
idea to review this information before you start your trip.
Check periodically
to see that all hitch nuts and bolts
are tight.
Engine Cooling When Trailer Towing
Your cooling system may temporarily overheat during
severe operating conditions. See Engine Overheating
on page
5-33.
4-43

Section 5 Service and Appearance Care
Service ............................................................ 5.3
Doing Your
Owr? Service Work ......................... 5-4
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
............................... 5-7
Filling Your Tank
............................................ 5-7
Filling a Portable Fuel Container
....................... 5-9
Checking Things Under the Hood .................... 5-10
Hood Release
.............................................. 5-10
Engine Compartment Overview
....................... 5-12
Engine Oil
................................................... 5-18
Supercharger Oil
.......................................... 5-24
Engine Air CleanedFilter
................................ 5-25
Automatic Transaxle Fluid
.............................. 5-27
Engine Coolant
............................................. 5-30
Radiator Pressure Cap
.................................. 5-33
Cooling System
........................................... -5-36
Power Steering Fluid
..................................... 5-46
Windshield Washer Fluid
................................ 5-48
Engine Overheating
....................................... 5-33 Brakes
........................................................ 5.49
Battery
........................................................ 5.52
Jump Starting
............................................... 5-53
Bulb Replacement .......................................... 5-60
Halogen Bulbs
.............................................. 5-60
Headlamps
.................................................. 5-60
Front Turn Signal and Sidemarker Lamps
........ 5-62
Center High-Mounted Stoplamp (CHMSL)
......... 5-63
Taillamps, Sidemarker and Back-up Lamps
...... 5-64
Replacement Bulbs
....................................... 5-66
Windshield Wiper Blade Replacement .............. 5-67
Tires ............................................................. -5-68
Inflation
-- Tire Pressure ................................ 5-68
Tire Inspection and Rotation
........................... 5-69
When It
Is Time for New Tires ....................... 5-70
Buying New Tires
......................................... 5-71
Uniform Tire Quality Grading
.......................... 5-72
Wheel Replacement
...................................... 5-73
Headlamp Aiming ........................................... 5-59
Wheel Alignment and Tire Balance
.................. 5-73
Tire Chains
.................................................. 5-75
If a Tire Goes Flat ........................................ 5-76
Changing a Flat Tire
..................................... 5-76
Compact Spare Tire
...................................... 5-87
5- 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 or
if you need to add coolant to
your radiator, see Engine Overheating on page
5-33.
A 50/50 mixture of clean, drinkable water and
DEX-COOL@ engine 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.
Let the warning lights and gages work as
they should.
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.
What to Use
Use a mixture of one-half clean, drinkable water and
one-half DEX-COOL@ engine coolant which won’t
damage aluminum parts. If you use this coolant mixture,
you don’t need to add anything else.
1 ---.-.g only p n water to your c 3 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
CAUTION: (Continued)
I
5-30

Adding Coolant
If you need more coolant, add the proper DEX-COOL@
coolant mixture at the coolant recovery tank, but be
careful not to spill it.
If the coolant recovery tank is completely empty, add
coolant to the radiator. See Engine Overheating
on page 5-33.
Turning -.le radiator pressure cap when the engine and radiator are hot can allow steam and scalding liquids to blow out and burn
you badly.
With the coolant recovery tank,
you will almost never have to add coolant at
the radiator. Never turn the radiator pressure
cap
-- even a little -- when the engine and
radiator are hot. 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.
Occasionally check the coolant level in the radiator.
For information on how to add coolant to the radiator,
see Cooling System
on page 5-36.
5-32

Radiator Pressure Cap
Notice: Your radiator cap is a pressure-type cap
and must be tightly installed to prevent coolant
loss
and possible engine damage from overheating.
Be sure the arrows on the cap line up with the
overflow tube
on the radiator filler neck.
The radiator pressure cap is located in the front of the
engine compartment on the passenger’s side, near
the diagonal cross brace. See Engine Compartment
Overview on page
5-12 for more information on location.
Engine Overheating
You will find a coolant temperature gage and a warning
light concerning an overheated engine condition on
the instrument panel cluster. See Engine Coolant
Temperature Gage
on page 3-31 and Engine Coolant
Temperature Warning Light
on page 3-31.
Overheated Engine Protection
Operating Mode
This emergency operating mode allows your vehicle to
be driven tu
a safe place in an emergency situation.
If an overheated engine condition exists, an overheat
protection mode which alternates firing groups of
cylinders helps prevent engine damage. In this mode,
you will notice a significant
loss in power and engine
performance. The engine coolant temperature gage will
indicate an overheat condition exists. 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”
ir
the Index.
5-33

He !r : I r8 r hoses, ar 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, with the engine on, check
to see
if the electric engine cooling fans are running.
If the engine is overheating, both fans should be
running.
If they aren’t, your vehicle needs service.
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
Recovery Tank
If you haven’t found a problem yet, but the coolant level
isn’t at the COLD mark, add a
50/50 mixture of clean,
drinkable water and DEX-COOL@ engine coolant at
the coolant recovery tank. See
Engine Coolant on
page 5-30 for more information.
5-38