The contact owns a 2018 Kia Optima. The contact stated that while driving at an undisclosed speed, the vehicle failed to accelerate and failed to exceed 52 MPH. The vehicle shut off. The contact stated that the engine was running rough while stationary and the vehicle shut off without warning. The vehicle was taken to an Auto Parts Store, where it was diagnosed, and it was determined that the vehicle was in LIMP Mode with knock sensor codes displayed. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 136,000.
2018 Kia Optima: engine knocking or ticking
23 of the 233 complaints about the 2018 Kia Optima describe engine knocking or ticking.
- owner complaints
- 23
- of this car's complaints
- 10%
- typical mileage
- 98,000
- recalls
- 0
Is there a fix? 58 service bulletins cover this area of the car. See below
Engine knocking or ticking by model year
What owners say
The contact owns a 2018 Kia Optima. The contact stated that while driving at an undisclosed speed, there was an abnormal odor and a knocking sound coming from the engine. The vehicle was taken to the dealer; however, the dealer was unable to duplicate the issue. The vehicle was not repaired. The issue persisted. The contact stated that the vehicle was later returned to the dealer to be repaired under a service campaign involving the engine control unit (ECU). Shortly after the vehicle was repaired, the ECU failure message was displayed. The vehicle subsequently became inoperable. The vehicle was not repaired. The manufacturer was notified of the issue. The approximate failure mileage was 1,500.
2018 Kia Optima LX, 2.4L GDI Theta II engine. Approximately 128,000 miles. Reporting severe internal oil consumption that has progressed to engine misfire and shaking, consistent with late-stage Theta II connecting rod bearing failure. The vehicle is now unsafe to drive and has been parked. Timeline: Purchased as a Certified Pre-Owned vehicle in December 2021. Excessive oil consumption began shortly after purchase. For approximately 4.5 years I have added about 1 quart of oil every 2 weeks to keep the engine from running dry. No external leaks have ever been found by any mechanic. Multiple independent mechanics attempted diagnosis and repair over this period. None resolved the issue. The vehicle has now developed a pronounced shake and apparent engine misfire, the textbook progression to rod bearing failure documented in the federal safety agency investigation PE19-004 and prior recalls/campaigns 17V‑224, SC147, and SC172. Safety concerns: Sudden engine seizure or stall at highway speed creates a serious crash risk for me and surrounding traffic. Theta II 2.4L GDI rod bearing failure has been associated with under-hood fires. The defect develops gradually with no warning to the driver beyond elevated oil consumption, which is frequently dismissed as normal until catastrophic failure occurs. I am filing this complaint to document the failure and to add to the federal safety agency's data on the Theta II GDI 2.4L engine in 2018–2019 Optimas. This model year was excluded from the original 2017 recall but is included in the Hyundai and Kia Engine Litigation class settlement and the lifetime engine warranty extension. My vehicle's symptoms match the defect pattern exactly. I will pursue warranty engine replacement, but I want this safety failure on the federal record regardless of how Kia responds.
My engine is under the Kia class action lawsuit for the KDS with the rod bearing clearance issues. I have done all my oil changes with paper work available. I got the update to the ECU several years ago as needed to be covered. Now my engine has failed and I took to the dealer to check but they said I didn't have a specific code and that they can't do any testing to verify it would be under the warranty. I called Kia Customer Care and have talked to them several times. They have told me there wasn't a need for the code and that the dealer could do other testing. The dealer stated that they can't do the BCT test due to a cylinder not having compression. I told Kia this is all related to the bearing going out and they said they can't do anything if the dealer said it's not under warranty. So I have now been going in circles with kia and dealer since 11/18/25. I sent kia another email on 12/15/25 and another on 12/18/25 due to not receiving a response. It's now 12/23/25 and still no response. They have a service bulletin that I seen online that was for dealers if any issues with testing they had other options but still nothing has been done.
I was driving on the highway with my children and the engine started to knock and lock up. I had to swerve onto an exit and roll into a gas station. My check engine light was on. I had it serviced in 2023 at a kia dealership. I had electrical issues to my battery that I opted to get fixed elsewhere. The dealership was aware of the recall on my engine, when I had it towed to them in 2025. Dealership said I opted out of a recall on my engine.
My 2018 Kia Optima went into limp mode while exiting the freeway. I had it scanned and received a P1326 code, which is directly tied to the known engine knock sensor / bearing wear issue in Kia models. The engine light came on and the car lost power suddenly. This created a very unsafe situation. I contacted Kia, and they confirmed that my VIN is not included in the engine recall (KSDS campaign), even though my symptoms exactly match the covered vehicles. I am now stuck with an undriveable car and no recall coverage, even though I’m facing the same failure risk. I believe this VIN should be included, and that this is a clear safety issue. I am requesting the federal safety agency to investigate and push Kia to expand coverage to include more affected vehicles.
The car is literally burning through oil so bad every other week I am putting more in, the electrical system continues to fail and shorts, the motor sounds like it is ticking now due to the oil consumption.
I am the current legal owner of a 2018 Kia Optima Hybrid (VIN: [XXX] ), which has an open safety recall under campaign number SC218Y3 (DTC P1326 – Knock Sensor Detection System / ECU Update / Possible Engine Repair). I attempted to schedule the recall repair with Martin Kia in Newark, Delaware. However, the service department refused to perform the recall service on the basis that I purchased the vehicle from an auction and do not have prior service records. This denial is a clear violation of federal recall regulations. As stated by the federal safety agency, all safety recall repairs must be completed free of charge regardless of ownership history or how the vehicle was purchased. I am now left with a potentially dangerous vehicle that Kia refuses to service, despite an active recall on file. This situation is unacceptable and puts me, as well as other road users, at risk. I respectfully request that the federal safety agency investigate Kia’s non-compliance and ensure they are held accountable for refusing to fulfill their legal obligations regarding this recall. I am willing to provide proof of ownership and any supporting documentation. Thank you Best regards My Contact Info: [XXX] [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Increased oil consumption with needing oil added and or changed half way before date or milage stated, oil changes performed by Kia dealer. Car staling and engine knocking while driving. Burnt smell while driving.
The contact owns a 2018 Kia Optima. The contact stated while driving approximately 40 MPH, the accelerator pedal was depressed; however, the vehicle failed to respond as needed. The contact stated that there was an abnormal growling sound coming from under the floorboard, and the engine was making an abnormal knocking sound. The contact stated that the RPM gauge was revving high while depressing the accelerator pedal; however, the vehicle failed to respond. The contact pulled over and turned off and restarted the vehicle; however, the vehicle was not running normally. The contact stated that the failure was a recurring failure. Additionally, the contact stated that vehicle was consuming approximately one quart of engine oil per week and the transmission was hesitating and was making the vehicle jerk while shifting gear. The contact had taken the vehicle to an independent dealer, but the vehicle was not diagnosed or repaired. The manufacturer was informed of the failure. The failure mileage was 76,270.
Have completed 4 oil consumption tests and replaced knock sensor and now have knocking in the engine
My vehicle is constantly running out of oil within a 30 day period and I constantly getting an oil change. I was advised to get an oil consumption test at the dealer and was out of oil in 3 weeks. I was told that I have a warranty, however, it's only if the rod bearings are an issue. I think my engine should be replaced without paying a $300 diagnostic fee that might get refunded without an exact time frame.
Service bulletins that may apply
- Voluntary emissions service campaign: theta II 2.4L GDI emissions: ECM logic improvement (SC340 revision 5)
- Voluntary emissions service campaign: theta II 2.4L GDI emission secm logic improvement (SC340 rev 4)
- Voluntary emissions service campaign: owner notification (SC340 flight 103 / jf)
- Voluntary emissions service campaign: theta II 2.4L GDI emissions ECM logic improvement (SC340)
- Voluntary emissions service campaign: owner notification (SC340 flight 101 / jf)
- Voluntary service campaign: theta II 2.4L GDI emissions ECM logic improvement (SC340)
- Voluntary emissions service campaign: owner notification (SC340 flight 102 / jf)
- Voluntary emissions service campaign: theta II 2.4L GDI emissions ECM logic improvement (SC340)
Related recalls
No recalls on record for this model year.
Questions about the 2018 Kia Optima knocking
Is engine knocking or ticking a common problem on the 2018 Kia Optima?
23 of 233 owner complaints about the 2018 Kia Optima (10%) mention engine knocking or ticking. The model year with the most reports is 2015.
Is there a recall or service bulletin for this on the 2018 Kia Optima?
There are 0 recalls and 58 service bulletins for the same area of the car. Check them below with your VIN.
Other symptoms on the 2018 Kia Optima
Oil consumption 54Check engine light 39Engine failure 30Stalling 29Jerking 15Fire or smoke 13Headlights 13Misfire 11Loss of power 10Won't shift 8Hesitation 7Fuel pump 6Won't start 6
VIN decoder
See the problems and recalls for an exact car
Buying a used 2018 Kia Optima?
Check the exact car before you pay: accidents, salvage or flood titles, odometer readings and previous owners.
Check its history