Kia Optima engine problems, 2016–2020
1,005 of the 1,667 complaints owners filed with NHTSA about the Kia Optima 2016–2020 name the engine (NHTSA’s “Engine” heading — the engine and its cooling system). The loudest years: 2016 (451), 2017 (200), 2018 (152). Filed under the same heading across these years: 4 manufacturer bulletins, 1 recall campaign, 2 NHTSA investigations. Every figure is a linked federal record; none is a failure rate, none a repair cost, and none a verdict on one car.
Kia Optima engine problems by model year
Source: NHTSA complaints, recalls, investigations and manufacturer communicationsOne row per model year on file, newest first. A year marked in depth has its own page: the complaints, the owners’ words and every document under this heading for that year.
| Model year | Complaints naming the engine | Share of the year’s | Typically at | On file under the heading | |
|---|---|---|---|---|---|
| 2020 in depth | 108 | 73% | 116k | 74 TSBs · 1 investigation | the record → |
| 2019 in depth | 94 | 45% | 75k | 88 TSBs · 1 investigation | the record → |
| 2018 in depth | 152 | 63% | 70k | 97 TSBs · 1 recall · 2 investigations | the record → |
| 2017 in depth | 200 | 66% | 74k | 100 TSBs · 1 recall · 2 investigations | the record → |
| 2016 in depth | 451 | 59% | 91k | 123 TSBs · 1 investigation | the record → |
Two things the counts carry that are not the car: how many of each year were sold, and how long each has been on the road — an older year out-counts a newer one before anything is wrong with it. The share column is the honest comparison across years: what part of that year’s complaints named the engine. Nothing here is a rate.
When the engine complaints were filed, and at what mileage
Source: NHTSA complaint databaseFiled per calendar year, every model year together: 2016: 2 · 2017: 9 · 2018: 13 · 2019: 44 · 2020: 40 · 2021: 50 · 2022: 127 · 2023: 237 · 2024: 188 · 2025: 193 · 2026: 102
Across the model years, half of the 297 owners who gave an odometer reading reported the engine problem between 51,000 and 111,000 miles. A median of reports, not the life of a part.
In owners’ own words
Source: NHTSA complaint databaseFiled with NHTSA by the people who own these cars, about the engine, from the model years with the most to say. Quoted as written, with anything identifying removed; unverified reports — what was said, not a finding that it was true.
For the 2nd year, my Kia would not start in 32 degree weather in big bear, ca. This is an annual trip & took my Kia. The lights, radio all turn on but the engine will not start. I have to wait until noon for the sun to warm up the car & then it's back to normal.
I have been experiencing issues with my 2016 Kia Optima since I purchased it on september, 5th 2016. A short time after owning my new vehicle, first the car started to hesitate when starting as if it was struggling to start, the push button would turn red and the indicator lights would light up on the dashboard as if the key was not…
The contact owns a 2017 Kia Optima. The contact stated that while driving approximately 50 MPH, there was an abnormal knocking sound coming from the engine compartment. The contact stated that the check engine and oil warning lights illuminated and then turned off independently.
I was driving the vehicle home on the freeway after just buying it. I had only driven it for about 35-40 minutes and after 5 minutes the ev battery was drained completely and the car was running in hybrid mode. The vehicle suddenly lost all its power and a warning light came on flashing saying "check hybrid system turn off engine".
The contact owns a 2018 Kia Optima Hybrid. The contact stated that while operating the vehicle, the message "Turn Engine Off Immediately" was displayed, and the vehicle decelerated to 35 MPH and stalled. The vehicle was towed to the local dealer who diagnosed that the engine was faulty and needed to be replaced.
What is on file about the engine, across the years
Source: NHTSA recalls, investigations and manufacturer communicationsRecall campaign filed under this heading, any model year
- 21V844000 CriticalOct 29, 2021 · 10,731 vehicles
- Kia Motors America (Kia) is recalling certain 2017-2018 Optima Hybrid and Optima Plug-In Hybrid vehicles. The connecting rod bearings inside the engine may wear prematurely, which can result in engine damage.
NHTSA investigations
- DP22003 Loss of Motive Poweropened Sep 12, 2022 · closed Dec 12, 2023
- The National Highway Traffic Safety Administration (NHTSA) received a letter dated July 13, 2022, petitioning the Agency to initiate a safety defect investigation into loss of motive power allegations attributed to oil drain pan assembly failures on certain Hyundai Motor America, Inc. and Kia America, Inc. vehicles spanning Model Years (MY) 2005-2021. The Petitioners cited examples of complaints i…
- EA21003 Engine Firesopened Dec 22, 2021 · closed Feb 5, 2024
- On March 29, 2019, the Office of Defects Investigation (ODI) opened two Preliminary Evaluations (PE19-003 on Hyundai and PE19-004 on Kia) to broadly investigate incidents of non-crash fires (regardless of origin or operational status of the vehicle) on various model year Hyundai and Kia vehicles. During the PE investigations, Hyundai and Kia issued several recalls to address vehicle fires, includ…
4 manufacturer bulletins filed under this heading, any model year
- Apr 4, 2026
- VOLUNTARY EMISSIONS SERVICE CAMPAIGN: THETA II 2.4L GDI EMISSIONS: ECM LOGIC IMPROVEMENT (SC340 REVISION 5) - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information to upgrade the Electronic Control Module ‘ECM’ system software for certain 2016-2020MY Optima, 2016-20
- Mar 18, 2026
- PRODUCT IMPROVEMENT CAMPAIGN: OWNER RENOTIFICATION (PI2104 FLIGHT 501) - This document is the owner renotification advising that Kia is conducting a Product Improvement Campaign to perform a software update on 2014-2016 MY Optima Hybrid vehicles equipped with 2.4-liter MPI engines to protect the engine from excessive connecting rod bearing damage. The update will be done free of charge and will on
- Apr 3, 2025
- TECHNICAL SERVICE BULLETIN: EXCESSIVE OIL CONSUMPTION NU/GAMMA/THETA/KAPPA ENGINES - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information on diagnosing and/or repairing some 2011-2024MY vehicles (refer to the table on pages 9 and 10 for applicable models and engine
- Feb 28, 2025
- TECHNICAL SERVICE BULLETIN: EXCESSIVE OIL CONSUMPTION NU/GAMMA/THETA/KAPPA ENGINES - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information on diagnosing and/or repairing some 2011-2024MY vehicles (refer to the tables on pages 8-9 for applicable models and engine), w
Every one filed under the heading is listed. Quote the document number at a service desk — it is a diagnosis the maker has already written down.
Other systems with a record on the Kia Optima
Source: the same filesEvery system, every model year: Kia Optima problems by year →
Common questions
Source: NHTSA complaint database, recalls and manufacturer communicationsWhich Kia Optima years have the most engine complaints?
2016, 451; 2017, 200; 2018, 152. Raw counts, and an older year has had longer to collect them; by share of each year's own complaints the loudest is the 2020 (73%).
Is there a recall for the engine on the Kia Optima?
Yes — one campaign is filed under this heading across these model years: 21V844000 (2018). A recall is matched by VIN, and applies to specific years; check yours at nhtsa.gov/recalls.
When do engine problems show up on the Kia Optima?
Owners who gave an odometer reading reported it at a median of 85,000 miles across the model years; half of them between 51,000 and 111,000. That is when reports cluster, not the life of a part.
What does NHTSA's "Engine" heading cover?
The engine and its cooling system. Owners choose the heading when they file, so it says which area of the vehicle the complaint is about, not which part failed.