PONTIAC GRAND PRIX 1999 Owners Manual

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5-9
With current trends in automotive styles and design, it is
essential that the correct towing equipment is used to
tow a vehicle. Your vehicle can be towed with wheel lift
or car carrier equipment. Don't have your vehicle towed
on the drive wheels, unless you must. If the vehicle must
be towed on the drive wheels, do not tow the vehicle
more than 500 cumulative miles (800 km) or exceed
50 mph (80 km/h). If these limitations must be
exceeded, then the drive wheels have to be supported
on a dolly.
Consult your dealer or a professional towing service if
you need to have your vehicle towed. See ªRoadside
Assistanceº in the Index.
Engine Overheating
You will find a coolant temperature gage and a warning
light about a hot engine on your instrument panel. See
ªEngine Coolant Temperature Gageº and ªEngine
Coolant Temperature Lightº in the Index. You also have
a low coolant light on your instrument panel. See ªLow
Coolant Lightº in the Index.
Overheated Engine Protection Operating
Mode (3100 V6 Engine Only)
This emergency operating mode allows your vehicle to
be driven to a safe place in an emergency situation.
Should an overheated engine condition exist, an
overheat protection mode which alternates firing groups
of three cylinders helps prevent engine damage. In this
mode, you will notice a significant loss in power and
engine performance. The low coolant light may come on
and the temperature gage will indicate an overheat
condition exists. Towing a trailer in the overheat
protection mode should be avoided.
NOTICE:
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 and change the oil.
See ªEngine Oilº in the Index.

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5-10 If Steam Is Coming From Your Engine
CAUTION:
Steam from an overheated engine can burn you
badly, even if you just open the hood. Stay away
from the engine if you see or hear steam coming
from it. Just turn it off and get everyone away
from the vehicle until it cools down. Wait until
there is no sign of steam or coolant before you
open the hood.
If you keep driving when your engine is overheated,
the liquids in it can catch fire. You or others could be
badly burned. Stop your engine if it overheats, and
get out of the vehicle until the engine is cool.
NOTICE:
If your engine catches fire because you keep
driving with no coolant, your vehicle can be
badly damaged. The costly repairs would not be
covered by your warranty. If your vehicle has the
3100 V6 engine, see ªOverheated Engine
Protection Operating Modeº in the Index.

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5-11 If No Steam Is Coming From Your Engine
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:

Climb a long hill on a hot day.

Stop after high
-speed driving.

Idle for long periods in traffic.

Tow a trailer.
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
-- or DRIVE (D) or THIRD (3).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, idle the engine for 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. If your vehicle has the
3100 V6 engine, see ªOverheated Engine Protection
Operating Modeº listed previously in this section.
You may decide not to lift the hood but to get service
help right away.

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5-12
Cooling System
When you decide it's safe to lift the hood, here's what
you'll see:
3100 Engine
A. Coolant Recovery Tank
B. Electric Engine Cooling Fans
C. Radiator Pressure Cap
3800 and 3800 Supercharged Engine
A. Coolant Recovery Tank
B. Electric Engine Cooling Fans
C. Radiator Pressure Cap

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CAUTION:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can injure you. Keep hands, clothing and tools
away from any underhood electric fan.
If the coolant inside the coolant recovery tank is boiling,
don't do anything else until it cools down.
The coolant level should be at or above the COLD mark
on the coolant recovery tank. If it isn't, you may have a
leak in the radiator hoses, heater hoses, radiator, water
pump or somewhere else in the cooling system.
CAUTION:
Heater and radiator 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.

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NOTICE:
Engine damage from running your engine
without coolant isn't covered by your warranty.
See ªOverheated Engine Protection Operating
Modeº in the Index.
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.
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.
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 ªEngine Coolantº in the
Index for more information.)
CAUTION:
Adding only plain water to your cooling system
can be dangerous. Plain water, or some other
liquid like 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.

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5-15
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.
CAUTION:
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.
When the coolant in the coolant recovery tank is at the
COLD mark, start your vehicle.
If the overheat warning continues, there's one more
thing you can try. You can add the proper coolant
mixture directly to the radiator, but be sure the cooling
system is cool before you do it.

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5-16
CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the radiator
pressure cap
-- even a little -- they can come out
at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap, is hot. Wait for the cooling system and
radiator pressure cap to cool if you ever have to
turn the pressure cap.
How to Add Coolant to the Radiator
NOTICE:
Your engine has a specific radiator fill procedure.
Failure to follow this procedure could cause your
engine to overheat and be severely damaged.

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5-17
1. You can remove the radiator pressure cap when the
cooling system, including the radiator pressure cap
and upper radiator hose, is no longer hot. Turn the
pressure cap slowly counterclockwise until it first
stops. (Don't press down while turning the
pressure cap.)
If you hear a hiss, wait for that to stop. A hiss means
there is still some pressure left.2. Then keep turning the pressure cap, but now push
down as you turn it. Remove the pressure cap.
CAUTION:
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.

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5-18
3. If you have the 3800 V6 engine, remove the
3800 Series II V6 engine cover shield to access the
bleed valve.
A. Clean the area around the engine oil fill tube and cap
before removing. Twist the oil fill tube, with cap
attached, counterclockwise and remove it.
B. If you have the supercharged engine, remove the nut
in the center of the cover shield.
C. Lift the engine cover shield at the front, slide the
catch tab out of the engine bracket and remove the
cover shield.
D. Put the oil fill tube, with cap attached, in the valve
cover oil fill hole until you're ready to replace the
cover shield.
Thermostat Housing
(3100 V6)Thermostat Bypass
Tube (3100 V6)