Kia Optima: Checking the Coolant Level
WARNING - Removing Radiator Cap

Check the condition and connections of all cooling system hoses and heater hoses. Replace any swollen or deteriorated hoses.
The coolant level should be full in the radiator and between F (Full) and L (Low) on the coolant reservoir tank when the engine is cool.
Check the coolant level using the dipstick attached to the reservoir cap.

If the coolant level is low, add enough coolant to bring the level to F, but do not overfill. If frequent additions are required, see an authorized Kia dealer or another competent repair center for a cooling system inspection.
Engine Cooling System
Changing CoolantOverdrive Clutch Control Solenoid Valve(OD/C_VFS). Description and Operation
Description
Overdrive clutch control solenoid valve(OD/C_VFS) is attached to the valve body.
This variable force solenoid valve directly controls the hydraulic pressure inside
the overdrive clutc ...
Components and Components Location
Component Location
1. Power door mirror
2. Power door mirror switch
3. Power folding mirror switch
...
Troubleshooting
Troubleshooting
1.
The lamp switch inputs can be
checked using the GDS.
2.
To check the input value of lamp
switch, select option "Body Control Module".
...