Chevrolet 2003 Impala Owner's Manual page 279

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 Engine Overheating on page 5-29.
A 50/50 mixture of clean, drinkable water and
DEX-COOL@ coolant will:
Give freezing protection down to -34°F (-37°C).
Give boiling protection up to 265°F (129°C).
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.
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