Kia Optima Hybrid 2017 Owner's Manual page 579

Maintenance
COOLANT
The high-pressure cooling system has
a reservoir filled with year round anti‐
freeze coolant. The reservoir is filled at
the factory.
Check the antifreeze protection and
coolant level at least once a year, at the
beginning of the winter season, and be‐
fore traveling to a colder climate.
CAUTION
• When the engine overheats from
low engine coolant, suddenly add‐
ing engine coolant may cause
cracks in the engine. To prevent
damage, add engine coolant slowly
in small quantities.
• Do not drive with no engine cool‐
ant. It may cause water pump fail‐
ure and engine seizure, etc.
9-26
Checking the coolant level
WARNING
n Removing radiator cap
• Never attempt to remove the radi‐
ator cap while the engine is oper‐
ating or hot. Doing so might lead
to cooling system and engine dam‐
age. Also, hot coolant or steam
could cause serious personal in‐
jury.
• Turn the engine off and wait until
it cools down. Use extreme care
when removing the radiator cap.
Wrap a thick towel around it, and
turn it counterclockwise slowly to
the first stop. Step back while the
pressure is released from the cool‐
ing system.
When you are sure all the pressure
has been released, press down on
the cap, using a thick towel, and
continue turning counterclockwise
to remove it.
(Continued)
(Continued)
• Even if the engine is not operating,
do not remove the radiator cap or
the drain plug while the engine and
radiator are hot. Hot coolant and
steam may still blow out under
pressure, causing serious injury.
The engine coolant and/or inverter
coolant level is influenced by the hybrid
system temperature. Before checking
or refilling the engine coolant and/or in‐
verter coolant, turn the hybrid vehicle
off.
WARNING
The electric motor (cool‐
ing fan) is controlled by
engine coolant tempera‐
ture, refrigerant pressure
and vehicle speed. It may
sometimes operate even
when the engine is not
running.
(Continued)