Kia Optima 2004 Owner's Manual page 106

ENGINE TEMPERATURE
GAUGE
H
C
This gauge shows the temperature of the
engine coolant when the ignition switch
is ON.
If the gauge pointer moves beyond the
normal range area toward the H position,
it indicates overheating that may damage
the engine.
Do not continue driving with an
overheated engine. If your vehicle
overheats, refer to "Overheating" in the
Index.
4-22
DRIVING YOUR VEHICLE
EMSA4020