Honda Civic 2008 Manual page 240

If Honda antifreeze/coolant is not
available, you may use another
major-brand non-silicate coolant as a
temporary replacement. Make sure it
is a high-quality coolant
recommended for aluminum engines.
Continued use of any non-Honda
coolant can result in corrosion,
causing the cooling system to
malfunction or fail. Have the cooling
system flushed and refilled with
Honda antifreeze/coolant as soon as
possible.
If the reserve tank is completely
empty, you should also check the
coolant level in the radiator.
Removing the radiator cap
while the engine is hot can
cause the coolant to spray out,
seriously scalding you.
Always let the engine and
radiator cool down before
removing the radiator cap.
2008 Civic Sedan
Engine Coolant
RADIATOR CAP
Except Si
1. Make sure the engine and radiator
are cool.
2. Relieve any pressure in the cooling
system by turning the radiator cap
counterclockwise, without
pressing down.
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