1999 PONTIAC FIREBIRD radiator

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5-20
4. 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
valve after the radiator is filled.
5. Then fill the coolant recovery tank to the
FULL COLD mark.
6. Put the cap back on the coolant recovery tank, but
leave the radiator pressure cap off.

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7. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fans.
8. 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.
9. Then replace the pressure cap. At any time during
this procedure if coolant begins to flow out of the
filler neck, reinstall the pressure cap. Be sure the
arrows on the pressure cap line up like this.

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5-22 How to Add Coolant to the Radiator
(V8 Engine Only)
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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3. Fill with the proper DEX-COOL
coolant mixture.
4. Continue to fill the radiator up to the base of the
filler neck.
5. Rinse or wipe the spilled coolant from the engine
and compartment.
6. Start the engine and allow it to run in idle for
approximately four minutes. By this time, the
coolant level inside the radiator will be lower. Add
more of the proper mixture through the filler neck
until the level reaches the base of the filler neck.7. Shut the engine off and replace the pressure cap.
Be sure the arrows on the cap line up like this.

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When you open the hood of the 3800 V6 engine you'll see:
A. Engine Coolant Reservoir
B. Battery
C. Radiator Cap
D. Engine Oil Fill CapE. Automatic Transmission Fluid
Dipstick (If Equipped)
F. Windshield Washer
Fluid Reservoir
G. Engine Cooling FansH. Engine Air Cleaner/Filter
I. Power Steering Fluid Reservoir
J. Engine Oil Dipstick
K. Brake Fluid Reservoir
L. Clutch Fluid Reservoir
(If Equipped)

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Rear Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when to change it. See
ªScheduled Maintenance Servicesº in the Index.
How to Check Lubricant
If the level is below the bottom of the filler plug hole,
you'll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of the filler plug hole.
What to Use
Standard Differential
Use SAE 75W
-90 Synthetic Gear Lubricant (GM
Part No. 12378261) or equivalent meeting GM
Specification 9986115.
Limited
-Slip Differential
To add lubricant when the level is low, use SAE 75W
-90
Synthetic Gear Lubricant (GM Part No. 12378261) or
equivalent meeting GM Specification 9986115. To
completely refill after draining, add 4 ounces (118 ml)
of Limited
-Slip Differential Lubricant Additive (GM
Part No. 1052358) or equivalent. Then fill to the bottom
of the filler plug hole with the Synthetic Gear Lubricant.
Radiator Pressure Cap
NOTICE:
Your radiator cap is an 18 psi (124 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, a GM 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, a GM thermostat
is recommended.

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6-28
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 ªEngine Overheatingº in the Index.
A 50/50 mixture of clean, drinkable water and
DEX
-COOL coolant will:

Give freezing protection down to
-34F (-37C).

Give boiling protection up to 265F (129C).

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 coolant which won't damage
aluminum parts. If you use this coolant mixture, you
don't need to add anything else.

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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.
NOTICE:
If you use an improper coolant mixture, your
engine could overheat and be badly damaged.
The repair cost wouldn't be covered by your
warranty. Too much water in the mixture can
freeze and crack the engine, radiator, heater core
and other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
NOTICE:
If you use the proper coolant, you don't have to
add extra inhibitors or additives which claim to
improve the system. These can be harmful.