1998 PONTIAC GRAND PRIX Engine

Cooling System
When you decide it’s safe to lift the hood, here’s what
you’ll see:
3100 Engine
3800 and 3800 Supercharged Engine
A. Coolant Recovery Tank
B. Electric Engine Cooling Fans
C. Radiator Pressure Cap
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’ A 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 overflow hose
in the coolant recovery tank. To
check the coolant level, remove the cap on the coolant
recovery tank. Check to make sure that the coolant level
is up to the COLD fill level on the hose attached to
the cap.
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.
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I A CAUTION: I
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 fined before you drive the vehicle.
NOTICE:
Engine damage if you keep running your engine
without coolant isn’t covered by your warranty.
See “Overheated Engine Protection Operating
Mode” in the Index.
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
wuter (preferably distilled) and DEX-COOL@ engine
coolant at the coolant recovery tank. (See “Engine
Coolant”
in the Index for more information.)
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 water and
DEX-COOL@ coolant.
5-20

I 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. 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.
5-21

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.
5-22

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 fist
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.
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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I" 3
3. After the engine cools, open the coolant air bleed
valve or valves.
3100 V6 (VIN Code M): There are two bleed valves.
One is located on the thermostat housing. The other
is located
on the thermostat bypass tube.
3800 V6 Supercharged engine (VIN Code 1):
There is one bleed valve. It is located on the
thermostat housing.
C
4. Fill the radiator with the proper DEX-COOL@
coolant mixture, up to the base of the filler neck.
(See "Engine Coolant" 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.
5. Rinse or wipe any spilled coolant from the engine
and the compartment.
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6. Then fill the coolant recovery tank to the
7. Put the cap back on the coolant recovery tank, but
FULL mark.
leave the radiator pressure cap
off.
‘f
8.
9.
Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for
the
engine cooling fans.
By this time, the coolant level inside the radiator
filler neck may be lower. If the level
is lower, add
more of the proper DEX-COOL@ coolant mixture
through the filler neck until the level reaches the
base
of the filler neck.
5-25