Pontiac 2002 Grand Prix Owner's Manual page 242

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.
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 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.
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