Kia Optima fan remains on after engine shutdown, causing battery drain despite new relay and battery on Kia Optima

Some Kia Optima owners report experiencing issues with the fan continuing to run after the engine is shut off, leading to battery drain even after replacing the relay and battery. This problem may stem from overheating or faults with the relay, potentially caused by defective temperature sensors, cooling fan issues, or problems with the ECU unit. Additionally, a sticking fan relay could be responsible, which is relatively inexpensive to replace. Some owners have found that the cooling fan relay might remain in an "on" position post-engine shutdown, or there may be faulty temperature sensors or thermostats preventing the fan from turning off as needed. It's also noted that if the engine is turned off and coolant flow is obstructed, heat can be trapped, necessitating the fan's operation for a few minutes after shutdown to assist in cooling. Therefore, it is advisable for owners to seek a thorough inspection by a qualified mechanic to accurately diagnose the fan issue in their Kia Optima.