Pontiac Sunbird Owner's Manual page 212

NOTICE
If you use an improper coolant
mix, your engine could overheat
and be badly damaged. The repair
cost wouldn't be covered by your
warranty.
Too much water in the
mix can freeze and crack the
engine, radiator, heater core and
other parts.
Adding Coolant-2.OL L4 Engine
To Check Coolant:
When your engine is cold, the coolant
level should be at F'ULL COLD, or a
little higher. When your engine is warm,
the level should be up to
FULL HOT,
or a little higher.
Your engine also has a thermostat
housing with a pressure cap. This cap
and the thermostat must be taken out to
add coolant.
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