Chevrolet 2000 Impala Owner's Manual page 235

If the coolant inside the coolant recovery tank is boiling,
don't do anything else until it cools down.
When the engine is cold, the coolant level should be at
or above the COLD mark on the coolant recovery tank.
To check the coolant level, look for the COLD mark on
the side of the coolant recovery tank that faces the
engine. Check to make sure that the coolant level is up
to the COLD fill level on the side of 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.
5-14
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.
NOTICE:
Engine damage from running your engine
without coolant isn't covered by your warranty.
See "Overheated Engine Protection Operating
Mode" in the Index.
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