Chevrolet 1994 Lumina Owner's Manual page 146

Problems on the Road
How
to Add Coolant to tht
Radiator:
NOTICE:
.'
' ,
Your engine has 'a'specific radiator
fill procedure. Failure to follow this
procedure could cause your engine
to overheat and be severely
damaged.
.
You can remove the radiator pressure
cap when the cooling system,
including the radiator pressure cap and
upper radiator hose, is no longer hot.
Turn the pressure cap slowly to the
left until it first stops. (Don't press
down while turning the pressure cap.)
If you hear a hiss, wait for that to stop.
A hiss means there is still some
pressure left.
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