2018 KIA OPTIMA Complaints

View complaints related to 2018 KIA OPTIMA. The complaints found here are submitted by actual consumers with first hand experience. There are more than 220 complaints submitted for the 2018 KIA OPTIMA. You can submit your own complaint to the NHTSA or call the Hotline, Monday-Friday 8am to 8pm at (888) 327-4236, TTY: (800) 424-9153.

  • 2018 KIA OPTIMA
    - Yonkers , NY

    My cars bulbs have been blowing on a regular basis for two years..some of the bulb connections are catching fire and exploding .Ive changed on numerous occasions but doesn’t matter even with new fittings…obviously an electric problem

    Source: NHTSA WEB SITE
  • 2018 KIA OPTIMA
    - Bessemer, AL

    The contact owns a 2018 Kia Optima. The contact stated that while driving at various speeds, the vehicle hesitated while depressing the accelerator pedal with the oil warning light flashing on the instrument panel. The contact's friend initially inspected the vehicle and discovered that the engine oil was empty. The vehicle was taken to a dealer where a diagnostic test was performed, and the mechanic discovered oil around the engine; however, the source of the leak was not discovered. The contact was informed that an engine valve was sealed and that the failure was repaired. Despite the repair, the failure persisted, and the oil light was frequently illuminated on the instrument panel. The engine oil level was checked and was extremely low. The dealer had not offered any additional assistance for the repair. The vehicle was not repaired. The contact made several attempts to reach the manufacturer but was unsuccessful. The failure mileage was approximately 10,000.

    Source: HOTLINE VEHICLE OWNERS QUESTIONNAIRE
  • 2018 KIA OPTIMA
    - Garden Grove, CA

    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 NHTSA to investigate and push Kia to expand coverage to include more affected vehicles.

    Source: NHTSA WEB SITE
  • 2018 KIA OPTIMA PHEV
    - Yucaipa, CA

    The contact owns a 2018 Kia Optima PHEV. The contact's daughter stated that while driving at an undisclosed speed, the high systems temperature switching to hybrid mode message was displayed. The contact stated that there was a two-hour delay for a full charge. The vehicle was taken to the dealer but was not diagnosed or repaired. The dealer informed the contact that the fluids in the vehicle needed to be changed. The vehicle wasn’t repaired; however, the failure recurred. The vehicle was taken back to the dealer, where it was not diagnosed or repaired. The contact was informed by the dealer to remove all the items located in the trunk of the vehicle. The vehicle was not repaired; however, the failure recurred. The vehicle was taken to the dealer, where it was diagnosed that the battery fan assembly had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 35,000.

    Source: HOTLINE VEHICLE OWNERS QUESTIONNAIRE
  • 2018 KIA OPTIMA
    - Martinez, GA

    My 2018 Kia Optima LX began using excessive oil (>3 quarts/1000 miles) just over 100K miles. I researched and found that the Theta II engine in my car is known for this. When I took my car to dealership (Stokes Hodges Kia, North Augusta, SC), with the check engine light on, they told me me plugs were fouled (they were just replaced 1 yr prior), cylinder 3 misfiring, and that I needed to pay a few thousand dollars to have repaired. When I asked them to guarantee the soaking process they recommended, they responded that they couldn't, that it "only worked 80% of the time." I have the KSDS download since 2019 and asked them to follow the guidelines of their TSB ENG 222 for the class action lawsuit and start a 1000 mile oil consumption test. they refused, basically telling me the only way to get a new engine from Kia, since my car is over 100K miles, is to drive it until the engine seizes. I expressed my fear for personal safety, but they wouldn't help me. I am original owner and have all services, etc documented. I called Kia customer affairs, then was told only local dealership could help. they stuck me in a loop between them without helping. Please help me.

    Source: NHTSA WEB SITE
  • 2018 KIA OPTIMA
    - Fontana, CA

    Kia is aware of the engine oil consumption causing misfires, failed emissions test, blowing a rod and engine lock up. THEIR SOLUTION WAS A CLASS ACTION LAWSUIT THAT STATE ONCE THE CAR IS LOCKED UP OR ROD HAS BLOWN THROUGH THE ENGINE THEN THEY WILL FIX IT. I HAVE HAD TO ADD OIL AT LEAST 3 TIMES EVERY 3000 MILES AND CONTINUE TO REPLACE THE OIL FILTER AS WELL. THE SPARK PLUGS HAVE BEEN REPLACED MUTLIPLE TIMES ALSO TO HELP WITH THIS ISSUE. KIA ADVISED THAT MY VEHICLE DID NOT FALL UNDER THIS RECALL EVEN THOUGH MY VEHICHLE IS HAVING THE SAME ISSUES AS THE RECALL STATES. THIS IS A KNOWN ISSUE WITH THIS MAKE AND MODEL AND THEY SHOULD NOT BE ABLE TO GET AWAY WITH SELLING DEFECTIVE VEHICLES AND NOT REPAIRING THE ISSUES THEY KNEW THEY HAD PRIOR TO SELLING THE VEHICLES. SOMETHING NEEDS TO BE DONE.

    Source: NHTSA WEB SITE
  • 2018 KIA OPTIMA
    - Villa Rica, GA

    Engine failed despite maintenance and repairs. The car is part of the active class action for Kia Engine Defects. The KSDS software was never installed as we were never notified about the recall by kia. As a result, Kia denied coverage under the engine defect class action settlement. We need this vehicle repaired or compensation for replacement

    Source: NHTSA WEB SITE
  • 2018 KIA OPTIMA
    - Elizabeth City, NC

    Purchased car about 4 months ago, before warranty ran out, the shop looked at it told me it was fine, it wouldn't accelerate. Few weeks later same issue but all my oil was gone, they found 11 things wrong with the vehicle, told me warranty wouldn't take care of it unless the engine blow up. The salesman Scottie Mitchell told me check Kia for recalls, called Kia 3 recalls, they were trying to finance another car higher, back wanted to know why the dealership didn't know about recalls, Kia place did call a Robert. One of the owners did know about recalls, why dealership didn't pass them on. They trying to sell me a higher vehicle to keep cover the cost of the one I got 1st

    Source: NHTSA WEB SITE
  • 2018 KIA OPTIMA
    - NASHUA, NH

    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.

    Source: NHTSA WEB SITE
  • 2018 KIA OPTIMA
    - Shelby, OH

    The 2.4L Theta II engine in my 2018 Kia Optima is failing, exhibiting excessive oil consumption, with oil loss documented at over 1 quart per 1,000 miles, leading to secondary failures in the catalytic converter, clogged with oil carbon and breaking into pieces that may damage the cylinder walls, and the spark plugs, which are fouled with carbon, causing misfires. The engine and related components remain intact and un-repaired, pending Kia’s required 3,000-mile consumption test. Safety of drivers have been put at significant risk. The excessive oil consumption and potential engine seizure threaten sudden loss of power, especially on freeways where car fails to accelerate to city and highway speeds, increasing the chance of a collision. The clogged catalytic converter poses a fire hazard, (reported by NHTSA investigations into Theta II) where oil leaks or debris can ignite on hot surfaces. Risk is heightened during the mandated 3,000-mile test as well. Problem has been confirmed by both a dealer and an independent service center as recent at 1 July, '25, documenting oil loss and new engine recommendation. Symptoms began with noticeable oil loss during oil changes, starting at least 1 quart per interval on May 10, 2023 (mileage 43,374), with the loss increasing over time. Misfires and RPM loss during acceleration first appeared after the oil valve gasket replacement in late May 2025, and freeway pickup issues became apparent around mid-June 2025. The full engine failure was confirmed by Spitzer on July 01, 2025.

    Source: NHTSA WEB SITE