1999 PONTIAC GRAND PRIX overheating

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2-79 Low Oil Level Light
The engine is equipped with
an oil level monitoring
system. When the ignition
key is turned to ON, the
LOW OIL LEVEL light
will briefly flash.
If the light does not flash, have it fixed so it will be
ready to warn you if there's a problem.
If the light stays on, stop the vehicle on a level surface
and turn the engine off. Check the oil level using the
engine oil dipstick. (See ªEngine Oilº in the Index.)
The oil level monitoring system only checks oil level
during the brief period when the ignition key is between
RUN and START. It does not monitor engine oil level
when the engine is running. Additionally, an oil level
check is only performed if the engine has been turned
off for a considerable period of time, allowing the oil
normally in circulation to drain back into the oil pan.
Engine Coolant Temperature Light
This light tells you that 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 off the road, stop the
vehicle and turn off the engine as soon as possible.
In ªProblems on the Road,º this manual shows what to
do. See ªEngine Overheatingº in the Index.

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2-80 Engine Coolant Temperature Gage
You have a gage that shows
the engine coolant
temperature. If the gage
pointer moves into the red
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 driving
conditions, you should pull off the road, stop the vehicle
and turn off the engine as soon as possible.
In ªProblems on the Road,º this manual shows what to
do. See ªEngine Overheatingº in the Index.
Low Coolant Warning Light
If this light comes on, the
system is low on coolant
and the engine may
overheat.
See ªEngine Coolantº in the Index and have the vehicle
serviced as soon as you can.
Fuel Gage
The fuel gage tells you
about how much fuel you
have left when the ignition
is on. When the indicator
nears E (EMPTY), you still
have a little fuel left, but
you should get more soon.

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4-39 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 want to drive in
THIRD (3), instead of DRIVE (D).
Parking on Hills
CAUTION:
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.

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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 then shift to PARK (P).
5. 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;

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 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 ªEngine Overheatingº
in the Index.

5-
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5-1
Section 5 Problems on the Road
Here you'll find what to do about some problems that can occur on the road.
5
-2 Hazard Warning Flashers
5
-2 Other Warning Devices
5
-3 Jump Starting
5
-8 Towing Your Vehicle
5
-9 Engine Overheating5
-12 Cooling System
5
-21 If A Tire Goes Flat
5
-22 Changing a Flat Tire
5
-32 Compact Spare Tire
5
-33 If You're Stuck in Sand, Mud, Ice or Snow

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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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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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If the fluid level is low, add only enough of the proper
fluid to bring the level into the cross
-hatched area on
the dipstick.
1. Pull out the dipstick.
2. Using a long
-neck funnel, add enough fluid at the
dipstick hole to bring it to the proper level.
It doesn't take much fluid, generally less than one
pint (0.5 L). Don't overfill.
NOTICE:
We recommend you use only fluid labeled
DEXRON
-III, because fluid with that label is
made especially for your automatic transaxle.
Damage caused by fluid other than
DEXRON

-III is not covered by your new
vehicle warranty.
3. After adding fluid, recheck the fluid level as
described under ªHow to Check.º
4. When the correct fluid level is obtained, push the
dipstick back in all the way.
Radiator Pressure Cap
NOTICE:
Your radiator cap is a 15 psi (105 kPa)
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.
When you replace your radiator pressure cap, an
ACDelco
cap is recommended.
Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant system. The thermostat stops the
flow of coolant through the radiator until the coolant
reaches a preset temperature.
When you replace your thermostat, an ACDelco


thermostat is recommended.