Pontiac 1998 Sunfire Owner's Manual page 229

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.
I
NOTICE:
~ ~~ ~ ~~
In cold weather, water can freeze and crack the
engine, radiator, heater core and other
parts. So
use the recommended coolant.
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