1999 PONTIAC GRAND PRIX radiator

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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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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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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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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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5-19
Thermostat Housing
(3800 V6)
4. After the engine cools, open the coolant air bleed
valve or valves.
3100 V6 engine: There are two bleed valves. One is
located on the thermostat housing. The other is
located on the thermostat bypass tube.
3800 V6 engine: There is one bleed valve. It is
located on the thermostat housing.
5. Fill the radiator with the proper DEX-COOL

coolant mixture, up to the base of the filler neck.
(See ªEngine Coolantº in the Index for more
information about the proper coolant mixture.)
If you see a stream of coolant coming from an air
bleed valve, close the valve. Otherwise, close the
valves after the radiator is filled.
6. Rinse or wipe any spilled coolant from the engine
and the compartment.