Kia Optima DL3 Quiz
Engine Mechanical System

Cooling System

In this manual: Engine Mechanical System
General Information — 8Advanced Driver Assistance System (ADAS) — 21Maintenance — 27Engine Mechanical System — 45Engine Electrical System — 11Emission Control System — 11Engine Control System/Fuel System — 25Automatic Transmission — 20Drive Shaft and Axle — 7Suspension System — 22Steering — 7Restraints — 11Brake System — 22Body (Interior and Exterior) — 116Body Electrical System — 90Heating, Ventilation, and Air Conditioning — 32
~2min read

Troubleshooting

Engine Overheating Troubleshooting

Inspection Remedy
Visual Inspection Check for lack of coolant in the coolant reservoir. Recheck after adding coolant.
Check for coolant contamination after removing the reservoir tank cap.
Recheck after replacing the coolant.
Inspect the coolant hoses (radiator hoses, oil cooler hoses, etc.). After reinstalling the hoses and clamps, recheck for leaks.
Inspect the installation area of the water outlet connection for leaks. Recheck for leaks after replacing the O-ring.
After tightening to the specified torque, recheck for leaks.
Inspect the drive belt (for normal operation of the water pump). Adjust the drive belt tension or replace the belt.
Inspect the water pump gasket mounting area for leaks. Recheck for leaks after replacing the gasket.
After tightening to the specified torque, recheck for leaks.
Inspect the coolant temperature sensor, the cooling fan connector, and the wiring harness. Reconnect any loose connector.
Replace the related part if the connector terminal is damaged.
Check the operation of the cooling fan.
- Check the operation by turning the A/C heater control on and off.
Check the condition of the ground cable installation.
Diagnostic Device Check the self-diagnostic trouble code using the KDS. Check the coolant temperature sensor, wiring, connector, etc.
Inspection of the Unit Inspect the water pump impeller. Replace the water pump.
Check for foreign material and the condition of the thermostat valve. Inspect the unit after removing foreign material.
Check whether the thermostat valve sticks.
- Immerse the thermostat in water heated above 95 °C, then heat for at least 3 minutes to check valve lift.
Check the valve lift.
- Replace the thermostat if the valve lift is below specification or the valve is stuck.

Test yourself

A quick Kia Optima DL3 quiz: every answer comes with an explanation and a link to the manual page.