2018 Kia Optima engine problems

Updated from NHTSA data · How we count

135 owners have reported engine problems with the 2018 Kia Optima, 65% of all complaints about this model year. The typical problem appeared around 82,000 mi.

Engine complaints
135
Crashes
1
Fires
6
Injuries
0
Related recalls
0
Median mileage
82,000 mi

Specific components reported

Engine covers: stalling, loss of power, oil consumption, overheating.

ComponentComplaints
Engine123
Engine and engine cooling11
Engine and engine cooling:engine:oil/lubrication2
Engine and engine cooling:engine:engine control module (ecu/ecm)1

Engine complaints across Kia Optima years

2200752008420098201085201121320124152013183201449820154022016157201713520189220191072020
Engine complaints by model year. The 2018 is highlighted.

Mileage when the problem appeared

2Under 10k310k–30k330k–60k1460k–100k13100k–150k150k+
Complaints that list mileage, grouped by odometer reading.

Related recalls

No recalls on file.

What owners say

  1. Filed Sep 8, 2026126,000 miFLTowedEngine
    The contact owns a 2018 Kia Optima. The contact stated that upon starting the vehicle, the vehicle jerked abnormally. The failure persisted while driving, and the vehicle lost motive power. The contact was able to restart the vehicle; however, the failure persisted while driving. The vehicle was towed to a dealer to be repaired under an unknown recall for an engine software update and key fob replacement; however, the dealer failed to honor the recall repair and recommended…
    NHTSA complaint #11762830 · source
  2. Filed Aug 20, 2026136,000 miGAEngine
    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…
    NHTSA complaint #11758363 · source
  3. Filed Jul 9, 2026PAEngine
    I’ve had my 2018 kia optima for round about two years.I only got this car because they refused to replace my previous engine on my 2015 Kia optima,even though I had a warranty but that’s another story(Kia on the Blvd).This car have given me problems from the start.Going through oil in less than a month,which they can never find a leak,not being able to go over a certain speed before I start to hear noises.Ive complained about noises,they act like they can’t hear,and said…
    NHTSA complaint #11749282 · source
  4. Filed Jun 25, 2026MOEngine
    The car burns oil within a week of getting an oil change. It was only driven a 200 miles before all of the oil was burned out. This has been a consistent issue with this car that the oil burns at an extreme rate. This is a safety risk as it could lead to engine overheating, the engine could stall out due to the fast burning of the oil, or a potential fire hazard while driving. The oil light will come on for a second and at that point, the oil is already EXTREMELY too low. I…
    NHTSA complaint #11746528 · source
  5. Filed Jun 23, 20261,500 miIDEngine
    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…
    NHTSA complaint #11745997 · source
  6. Filed May 6, 2026121,000 miOKBody & StructureEngine
    The contact owns a 2018 Kia Optima. The contact stated that while attempting to accelerate from a standing start the vehicle had experience sever jerking and hesitation. Also, the vehicle has experience oil consumption problems and the contact constantly added engine oil. The cause of the failures were not determine. Also, the hood latch had malfunctioned and the hood could not opened to add oil to the engine. The cause of the failures were not determined. The local dealer…
    NHTSA complaint #11736008 · source
  7. Filed Apr 28, 2026VAEngine
    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…
    NHTSA complaint #11734333 · source
  8. Filed Apr 15, 2026GAEngine
    Consuming fuel to the amount of roughly 1/2 quart per 150 miles. Vehicle has been inspected by mechanic and the oil pan, oil filter, and PCV valve has been replaced and engine oil UV dye added and cycled with no leaks found. The risk is that if not rigorously checked often, the engine will malfunction because the car runs out of oil. I have had my mechanic checking this car since I purchased it in January 2026. We have had to replace the oil pan and do two full oil changes…
    NHTSA complaint #11731478 · source
  9. Filed Mar 11, 2026GABody & StructureEngineOther / Unknown
    My teenage daughter regularly drives this vehicle. The vehicle began experiencing significant oil consumption, oil leaks, and intermittent loss of power. During an early inspection at an independent repair facility, a check engine code P1326 was identified. Due to the symptoms and diagnostic code, the repair facility advised that the vehicle could be heading toward engine failure and recommended that the vehicle be taken to an authorized dealership because potential engine…
    NHTSA complaint #11723632 · source
  10. Filed Jan 9, 2026GAEngineOther / Unknown
    It started with the oil. I constantly have to add oil. when it first started that’s what I was doing just adding oil. Then it got worse the engine light started to come on and it no longer gives me the low oil warning. I took it to the dealership and it was there for about three weeks. They said that the car needed a system update, they updated it and i took it home after that. Its been about a year since then and my car is still having the same issue and getting worse. I…
    NHTSA complaint #11710029 · source
  11. Filed Jan 8, 2026GABrakesElectrical SystemEngine
    I turned the car off, it had difficulty turning back on and the brake pedal got really hard. I had to wait about 30-45 minutes and then I was able to get the car started and brake pedal back to normal and no lights. Recently, I left the car on to run into a shop real quick and come back out. When I got back to the car, the power steering light, battery, and warning light?(amber triangle with ! In the center of it) were all on. I rev the engine and the issue went away for a…
    NHTSA complaint #11709575 · source
  12. Filed Jan 7, 2026CAElectrical SystemEngineOther / Unknown
    I was sold an unsafe vehicle at J and J Auto house 6446 Wilshire Bl LA,CA 90022. Dealer withheld condition of car . Had car three months and was stranded on highway. Car was towed to Kia dealer and diagnosed with complete engine failure. Dealer will not honor limited warranty, shady sales practices withheld recall info during sale, won’t allow his mechanic to look at car, dodged calls, denied request to return car for refund
    NHTSA complaint #11709524 · source

Other 2018 Kia Optima problem areas

  • Other / Unknown (34)
  • Electrical System (28)
  • Brakes (14)
  • Lighting (14)
  • Transmission & Drivetrain (13)
  • Fuel, Hybrid & EV Propulsion (13)
  • Steering (9)
  • Acceleration & Cruise Control (8)
  • Airbags (6)
  • Body & Structure (6)
  • Seats & Seat Belts (4)
  • Driver Assistance & Safety Tech (4)
  • Wheels & Tires (2)
  • Suspension (1)
  • Visibility & Wipers (1)

Back to all 2018 Kia Optima problems →

Source: U.S. National Highway Traffic Safety Administration (NHTSA) Office of Defects Investigation public data. Complaints are submitted by owners and are not verified by NHTSA or by us; a complaint does not prove a defect exists. View this vehicle on NHTSA.gov Methodology