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, 2016-2020MY Sorento, 2017-2022MY Sportage vehicles equipped with 2.4L Theta II engines listed in the table below. Kia has become aware that certain 2016-2022MY vehicles equipped with 2.4L Theta II engines may have engine calibrations that were not optimized for emissions standards under certain specific co
full bulletin at NHTSA ↗2019 Kia Optima engine problems
moderate Owners of the 2019 Kia Optima have filed 60 NHTSA complaints about the engine, typically surfacing around 100,008 miles at roughly $3,100 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See engine across all vehicles →
Failure mileage
Complaints
60
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2015 Optima | 451 |
| 2016 Optima | 313 |
| 2017 Optima | 125 |
| 2018 Optima | 103 |
| 2019 Optima (this page) | 60 |
| 2020 Optima | 66 |
2fires
When does it fail?
Of the 60 engine complaints filed for the 2019 Kia Optima, here's the actual mileage breakdown — failures cluster heaviest at 125,000-150,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Owners have filed 60 engine complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
Engine accounts for 29% of all owner complaints filed against this vehicle, across 8 categories tracked.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
VOLUNTARY EMISSIONS SERVICE CAMPAIGN: OWNER NOTIFICATION (SC340 FLIGHT 104 ) - This document is the owner notification advising that Kia is conducting a Voluntary Emissions Service Campaign to improve the emissions software logic in the Electronic Control Module (ECM) for certain 2016-2020 MY Optima vehicles equipped with 2.4L Gas Direct Injection (GDI) engines to ensure compliance with emissions regulations.
full bulletin at NHTSA ↗TECHNICAL SERVICE BULLETIN: VOLUNTARY EMISSIONS SERVICE CAMPAIGN: THETA II 2.4L GDI EMISSION SECM LOGIC IMPROVEMENT (SC340 REV 4) - 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 2016-2022MY vehicles equipped with 2.4L Theta II engines listed in the table below. Kia has become aware that certain 2016-2022MY vehicles equipped with 2.4L Theta II engines may have engine calibrations that were not optimized for emissions standards under certain specific conditions. These calibrations
full bulletin at NHTSA ↗VOLUNTARY EMISSIONS SERVICE CAMPAIGN: OWNER NOTIFICATION (SC340 FLIGHT 103 / JF) - This document is the owner notification advising that Kia is conducting a Voluntary Emissions Service Campaign to improve the emissions software logic in the Electronic Control Module (ECM) for certain 2016-2020 MY Optima vehicles equipped with 2.4L Gas Direct Injection (GDI) engines to ensure compliance with emissions regulations.
full bulletin at NHTSA ↗TECHNICAL SERVICE BULLETIN: VOLUNTARY EMISSIONS SERVICE CAMPAIGN: THETA II 2.4L GDI EMISSIONS ECM LOGIC IMPROVEMENT (SC340) - 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 2016-2022MY vehicles equipped with 2.4L Theta II engines listed in the table below. Kia has become aware that certain 2016-2022MY vehicles equipped with 2.4L Theta II engines may have engine calibrations that were not optimized for emissions standards under certain specific conditions. These calibrations may c
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
2019 Kia Optimas with the 2.4L Theta II GDI engine are experiencing widespread internal engine failures centered on excessive oil consumption. Owners report the engine burning or consuming oil internally at alarming rates—some cite needing oil top-ups every 600–1500 miles or every 1–3 weeks, despite no visible external leaks. Oil light warnings come on unexpectedly shortly after fresh oil changes, and dipsticks show bone-dry levels when not due for service. Kia issued a service bulletin on March 1, 2022 citing "excessive oil consumption for 2011–2021 Optimas" and offering an engine "upgrade," but owners say they were not given a diagnostic test to confirm the issue first, and consumption persists afterward.
The oil intrusion into combustion chambers causes spark plugs to foul repeatedly—some owners replace plugs monthly. Check engine lights flash, misfires occur, and vehicles go into limp mode, restricting speed to 15–40 mph. Knock sensor codes are common; dealers replace the sensor, but failures recur. Root causes cited by mechanics include burnt or leaking valves, defective piston rings, compression loss, and severe sludge buildup, all pointing to a design or manufacturing defect in the Theta II platform rather than owner neglect.
Complete engine seizures and stalls are reported, occasionally preceded by rod knock sounds. In one case, the engine caught fire at 133,000 miles; another reports fire less than a year after a prior engine replacement. Owners document regular maintenance with synthetic oil, provide service records, and yet dealerships deny warranty claims once mileage exceeds 100,000 miles or claim warranty only covers actual seizure, not consumption itself. A prior class action settlement is referenced but no formal recall was issued, leaving owners unprotected and facing $5,000+ engine replacement costs or disputed warranty disputes with Kia Consumer Affairs.
Same Kia Optima engine reports on nearby years: 2016 · 2017 · 2018 · 2020
Failure modes owners describe
Excessive Oil Consumption
Engine burns or consumes oil internally at abnormal rates with no visible external leaks. Oil levels drop rapidly between scheduled oil changes—sometimes within 600–1500 miles of a fresh change. This forces owners into frequent top-offs or emergency oil addition to prevent engine seizure.
When: Reported from ~30,000 miles to 179,000 miles; many cases occur before 100,000 miles on 2019 models. Service bulletin issued 3/1/22 for 2011–2021 Optimas.
Symptoms owners cite: Oil light flashing or illuminating unexpectedly, even shortly after oil change; Oil dipstick reading nearly empty or bone-dry when not due for service; No visible leaks underneath or on engine exterior; Owner reports needing oil top-up every 1–3 weeks or every 600–2000 miles; Oil consumed faster after dealer 'upgrades' applied per TSB without diagnostic test
Codes mentioned: P0128 (Coolant Thermostat), Excessive oil consumption confirmed by leak-down tests at dealerships
Repairs/costs cited: Dealers and independent mechanics recommend long-block engine replacement, typically $5,000+. Some owners report being denied warranty coverage past 100k miles or being told warranty only covers actual engine seizure, not the consumption itself. Third-party warranties may decline coverage.
Recalls/TSBs owners mention: Kia issued a service bulletin on 3/1/22 addressing 'excessive oil consumption for 2011–2021 Optimas.' Owners report the TSB provided an engine 'upgrade' rather than a diagnostic test (DX test) to confirm the issue. Settlement from prior class action mentioned but details vague—Kia handling cases on rolling basis with no formal broad recall issued. Extended warranty programs claimed for Theta II engines but owners report difficult enforcement and denial when mileage exceeds 100k or when engine has not fully seized.
Cylinder Misfire / Oil Intrusion into Spark Plugs
Oil enters the combustion chamber and fouls spark plugs, causing cylinder misfires. Drivers report rough running, jerking, hesitation, and the need to replace spark plugs repeatedly—sometimes monthly.
When: Reported across mileage range; spark plug replacements begin as early as 70,000 miles and repeat multiple times within months.
Symptoms owners cite: Check engine light illuminates; often flashing, indicating active misfire; Rough idle, jerking, bucking, or shaking during acceleration; Poor acceleration; car goes into limp mode, limiting speed to 15–40 mph; Engine hesitation and rough takeoff; Oil present on spark plug and in cylinder when inspected; Spark plugs require replacement every 1–4 weeks or monthly despite normal usage
Codes mentioned: P0300 (Random / Multiple Cylinder Misfire Detected), P0301 (Cylinder 1 Misfire), P0302 (Cylinder 2 Misfire), P0304 (Cylinder 4 Misfire), DTC for Knock Sensor issues
Repairs/costs cited: Independent mechanics replace spark plugs and clean cylinders; however, the root cause (oil consumption/intrusion) is not addressed, so misfires recur. Some dealers blame sludge buildup. Full engine replacement recommended by mechanics when compression is lost.
Recalls/TSBs owners mention: No specific TSB or recall cited for this failure mode. Dealers often claim it is not covered under warranty once vehicle exceeds mileage thresholds or claim the consumer failed maintenance despite documented regular oil changes.
Knock Sensor Fault / Limp Mode Activation
Knock sensor malfunction causes check engine light (often flashing) and vehicle enters limp mode, severely restricting power and acceleration. Root cause appears linked to excessive oil consumption causing sludge, carbon buildup, or internal engine damage.
When: Reported at mileages ranging from ~57k to 95k+ miles.
Symptoms owners cite: Check engine light flashing on the dashboard; Vehicle immediately decelerates or goes into limp mode; Maximum speed drops to 15–40 mph despite accelerator input; Rod knock audible from engine or ticking sound; Knock sensor code read via OBD scanner; Often accompanied by low or no oil present in engine at time of failure
Codes mentioned: P0001 (Knock Sensor malfunction)
Repairs/costs cited: Dealers replace knock sensor; however, failure recurs. Owners report replacing knock sensor multiple times. Root cause (internal engine wear, sludge, or oil starvation) not addressed; temporary fix only.
Recalls/TSBs owners mention: No warranty coverage offered by dealers post-failure. Manufacturers state knock sensor replacement is not covered or claim warranty has expired. No recall or extended coverage program specifically for knock sensor faults cited.
Valve Damage / Compression Loss
Internal valves fail, burn, or leak, causing compression loss in one or more cylinders. Often diagnosed as burnt valve, broken valve seal, or defective piston oil rings. Owners report the mechanic states engine replacement is necessary.
When: Reported at mileages from 65,000 to 179,000 miles, though some claim these are design defects in the Theta II platform affecting 2017 and newer models.
Symptoms owners cite: Violent shaking or jerking while driving; Check engine light illuminates; Cylinder won't hold compression; Leak-down test reveals leaking valves; Oil floods into firing chamber; Engine rough, rough idle, loss of power
Codes mentioned: P0301 (Cylinder misfire codes tied to compression loss)
Repairs/costs cited: Engine replacement required; long-block assembly recommended. Cost equivalent to vehicle payoff in some cases ($5,000+). Some mechanics state engine seizure is imminent if driven.
Recalls/TSBs owners mention: Kia denies coverage under extended warranty, citing mileage threshold or expiration. Owners reference class action settlements and TSBs for Theta II platform, but claim Kia has not issued broad recalls. Some mention lifetime warranty on engine for certain model years but enforcement is inconsistent.
Complete Engine Failure / Seizure
Engine ceases operation entirely—either a sudden stall or complete failure requiring towing. Causes range from oil starvation to internal component failure (burnt valve, sludge, rod knock).
When: Reported at various mileages; some as early as 30,000 miles, others at 92,000+ miles. One case reported sudden fire at 133,000 miles post-failure.
Symptoms owners cite: Engine stops abruptly while driving; Burning smell from engine compartment (in one case, fire); Car enters limp mode and will not accelerate; Rod knock audible just before failure; Check engine light flashing before stall; No warning lights on (in at least one case), only flashing check engine light at moment of failure
Codes mentioned: No oil in engine at time of inspection (confirmed by service advisors)
Repairs/costs cited: Engine replacement only option. Towing required. Some owners report dealerships blame fuel pump as initial diagnosis, then later confirm engine damage after days of investigation with Kia engineers.
Recalls/TSBs owners mention: Kia engineers are consulted on some cases; referral to class action settlement mentioned. However, no rental car provided to customer, and timeline for repair unclear. One customer reports being told only 2 cylinders firing before complete failure. Settlement cited but case outcomes vary widely.
Engine Fire
Engine compartment catches fire while vehicle is in operation or immediately after stopping. At least one case involved a Good Samaritan using a fire extinguisher (ineffective), with fire department required to fully extinguish.
When: Reported at 133,000 miles in one detailed case. Another case reports engine caught fire less than a year after engine replacement due to prior recall.
Symptoms owners cite: Smoke visible from under the hood; Fire visible in engine compartment; No warning lights or alerts on dashboard prior to fire (in one case); Driver forced to exit vehicle quickly
Repairs/costs cited: Vehicle totaled by insurance. Not repaired.
Recalls/TSBs owners mention: No manufacturer response or investigation in the detailed narrative. One case reports dealership not answering phone calls when fire occurred.
Oil Pressure Warning Light / Sensor Issues
Oil pressure warning light illuminates intermittently or persistently, sometimes triggered by low oil but not always resolving after oil addition. Oil pressure sensor replaced, but light recurs. In some cases, the warning light does not trigger despite dangerously low oil levels.
When: Reported across multiple mileage ranges. One case noted light came on at 132,000 miles; another at 65,000 miles.
Symptoms owners cite: Oil pressure warning light illuminates; Light flashes on and off at takeoff or braking; Light persists even after oil change and dealer sensor replacement; In some cases, light never comes on despite oil being nearly empty (no warning to driver); Vehicle loses power while light is on
Codes mentioned: Oil pressure sensor fault (replaced but recurs)
Repairs/costs cited: Dealers replace oil pressure sensor (sometimes twice, using OEM part). Light may persist; root cause (low oil from consumption, sludge, or actual pump failure) not addressed.
Recalls/TSBs owners mention: No warranty coverage cited. Dealers advise customer to monitor oil level manually after every fill-up.
Sludge Buildup / Carbon Deposits
Excessive sludge accumulation inside engine, often found under the valve cover during inspection. Mechanics and dealers cite sludge as cause of misfire, oil consumption, and rough running, but owners dispute this is a maintenance issue when they follow scheduled oil changes with synthetic oil.
When: Reported at mileages ranging from 92,000 to 112,000 miles.
Symptoms owners cite: Sludge found under valve cover during inspection; Check engine light and misfire codes present; Rough running, jerking; Oil in cylinders and on spark plugs
Codes mentioned: Misfire codes (P0301, P0302, etc.)
Repairs/costs cited: Dealers often claim sludge is result of poor maintenance; however, some owners provide 6–8 recent oil change receipts with synthetic oil and claim dealer's TSB 'upgrade' was performed. Engine replacement recommended if sludge is severe.
Recalls/TSBs owners mention: Dealers use sludge finding to deny warranty, claiming inadequate maintenance. However, Kia issued TSB for excessive oil consumption in 2022, and some owners note they received only an 'upgrade' rather than a diagnostic test.
Synthesized from 60 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 4 most recent
Since January 2024 I have had to replace the spark plugs more than 3 times. It has also had to have an oil change done at least every two months regardless of the miles that were put in it. BURNING OIL LIKE CRAZY Mid October 2024 a full tune up was done as well as oil change and less than two weeks later it started bucking like a bronco and all oil was gone out of it. Check engine light is on and…
I purchased a used 2019 Kia Optima from a dealership in January 2025 with 103,000 miles. 11 months later it's burning oil. Every 2 weeks I have to add a quart of oil. I took it to my mechanic and they found cylinder 4 has been burning oil. They also found a technical service bulletin related to engine oil consumption. They recommended replacing long block assembly. They referred me to a Kia…
The contact owns a 2019 Kia Optima. The contact stated that the catalytic converter was previously replaced. The contact stated that while driving at 60 MPH, two weeks later, the check engine warning light illuminated, and the vehicle started misfiring. The contact drove to the residence. The vehicle was towed to an independent mechanic, where it was diagnosed and determined that the engine…
Defective piston rings leading to excessive oil consumption, spark plug deterioration, and potential engine failure.
Had engine trouble with your 2019 Kia Optima?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2019 Kia Optima?
It's a documented issue but not catastrophic. 60 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Across the 12 complaints that reported odometer mileage, most engine failures cluster between 65,000 and 133,000 miles, with the median around 100,008. A quarter of owners report trouble before 65,000; a quarter make it past 133,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2019/Kia/Optima.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.