In Sept the car oil light came on. The car was out of oil. Took it to shop and they could not find a leak. The car was filled with oil. Less than 1,000 miles later in Oct the same situation occurred again. The car was inspected an no leak was found but the oil was gone. In Dec after going 2 500 miles the same situation occurred again and another shop inspected and could not find out why. In all 3…
2016 Kia Optima engine problems
moderate 312 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
312
Recalls
0
Avg fix
$3,100
1crash
6fires
1injury
When does it fail?
Of the 312 engine complaints filed for the 2016 Kia Optima, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 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
Engine accounts for 42% of every owner complaint on file for this vehicle — the dominant problem area across 11 categories tracked.
Owners have filed 312 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.
The failure pattern owners describe
Buyer takeaway: A 2016 Kia Optima with the 2.4L GDI engine is a high-risk used purchase. Owners consistently report rapid oil consumption (1–6+ quarts per 1000 miles), premature bearing failure causing engine seizure and limp mode often without warning, and repeated spark plug fouling. Even with full maintenance records, Kia denies coverage citing mileage or lack of prior recall updates. Avoid unless you can verify a recent engine replacement or are willing to budget $8,000–$13,000 for engine replacement soon.
The 2016 Optima's 2.4L GDI engine emerges as a chronic failure platform across 309 complaints. The dominant failure mode is excessive oil burning—owners need to add 1–6 quarts per 1,000 miles, often with no visible leak. Oil light flickers intermittently or stays dark until the engine runs dry. Dealers apply a 1-quart-per-1,000-mile threshold for warranty coverage; owners burning 0.75–1.5 quarts fall into a gray zone where Kia offers nothing.
Engine seizure is the second major failure. Connecting rod bearings wear prematurely, and the engine seizes on the highway or in traffic without warning—no check-engine light beforehand in many cases. When the light does come on, it is often too late. Owners describe violent knocking, sudden loss of all power, and being stranded in the roadway at night. Kia issued recall SC147 for this defect, but only certain VINs qualify. Used-car buyers often have no record of the recall being performed and receive no notice, leaving them ineligible under Kia's interpretation.
Spark plugs foul repeatedly—owners report replacing them every 2–4 weeks due to carbon and oil fouling. Misfire codes (P0300–P0304) appear, then clear, then reappear. Dealers recommend combustion cleaning ($350–$700), but the root cause (oil burning) is never fixed. Limp mode recurs unpredictably, capping RPM at 1,500–2,000 mph and leaving owners unable to merge on highways or climb hills.
Kia's response centers on the KSDS software update and knock sensor replacement as a "fix," but owners report failure persisting or recurring after both. Warranty denials cite: failure to complete KSDS before the engine failed, mileage over 100K, purchase from a third party without recall notice, or absence of a specific knock sensor code at the moment of failure. One owner replaced an engine under warranty only to have the identical failure occur within a week of pickup. Another waited five weeks for an engine part after KSDS update caused failure. Repair costs run $5,500–$13,000; owners out of warranty have no recourse.
Same Kia Optima engine reports on nearby years: 2014 · 2015 · 2017 · 2018 · 2019
Failure modes owners describe
Excessive Oil Consumption
Engine burns or leaks oil rapidly, requiring top-offs every few hundred to 1000 miles. Owners report 1–6+ quarts consumed per 1000 miles, well above the 1-quart threshold dealers cite. No visible external leaks found in many cases; oil is burned internally or enters the combustion chamber.
When: Reported from 65K to 141K miles; some owners notice it immediately after purchase (used cars), others after 80K+ miles
Symptoms owners cite: Oil light flickering or illuminated; Needing to add oil every 1–3 weeks or every 300–500 miles; Burnt oil smell or blue smoke from exhaust on startup; Dry dipstick after short driving intervals; Oil dipstick showing low after an oil change within days or weeks
Codes mentioned: P0300 (misfire), P0301–P0304 (cylinder-specific misfire), Service engine soon light
Repairs/costs cited: Oil consumption tests (1000-mile observation) conducted by dealers; some dealers recommend combustion chamber cleaning ($350–$700). Owners cite costs of $5,500–$10,000 for full engine replacement. One owner reports paying $700 for engine cleaning; another cites need for PCV valve replacement. Oil consumption test results range 0.5 to 2+ quarts per 1000 miles; dealers apply a >1 qt/1000 mi threshold for coverage, leaving owners with marginal results (0.75–1.5 qt/1000 mi) uncovered.
Recalls/TSBs owners mention: KIA Technical Service Bulletin TSB 222 directs engine cleaning procedure. Some owners mention KSDS (Kia Smart Dual Sequential) software upgrade performed. Dealers cite powertrain warranty extending to 100K miles (standard) or 120K miles (extended in some cases). Owners report denial of coverage citing: (1) mileage over 100K; (2) failure to perform KSDS update prior to complaint; (3) consumption below 1 qt/1000 mi threshold; (4) classification as 'normal wear.' One case mentions Kia's refusal based on vehicle purchased from auto auction with multiple prior owners. No manufacturer-initiated recall cited for oil consumption alone in these narratives.
Engine Bearing/Rod Failure & Seizure
Connecting rod bearings wear prematurely, causing metal shavings to circulate. Engine seizes suddenly, often on highway, with loud knocking and loss of power. Vehicle enters limp mode, stalls, or becomes undriveable. Seizure can occur with no prior warning lights or after only brief warning (check engine light, knock detection).
When: Reported at 68K to 144K miles; some within months of purchase (used); often after KSDS update or spark plug replacement attempts
Symptoms owners cite: Loud knocking or clunking sound from engine; Sudden loss of power / severe deceleration without warning; Engine seizes and will not restart or only briefly restarts; Check engine light flashing (engine knock/misfire detection); Vehicle enters limp mode (RPM capped at 1,500–2,000); Violent shaking/shuddering while driving; Burnt oil smell from exhaust; Black smoke from tailpipe
Codes mentioned: P1326 (engine knock/failure), P0300 (misfire), P0301–P0304 (cylinder misfire)
Repairs/costs cited: Full engine replacement quoted at $8,500–$13,000 (parts and labor). One owner paid $9,735 for parts/labor at dealership. Dealers initially perform diagnostic scans, BCT (bearing condition test) reportedly taking 4–5 hours. Multiple owners cite engine was replaced 2–3 times, with failure recurring. Repair records show replacement of knock sensors, wiring harness, spark plugs, and ECU updates, but bearing failure persists or recurs. One case mentions metal shavings migrating through engine after 90K miles of damage.
Recalls/TSBs owners mention: Recall SC147 (NHTSA 17V-224) addresses connecting rod bearing wear and engine seizure for certain Optima model years and VINs. Owners mention 'lifetime warranty' on engine offered by Kia after initial knock sensor replacement or upon recall completion. However, Kia denies coverage citing: (1) vehicle not original owner; (2) no recall notification received (used car purchase without dealer contact); (3) KSDS update not completed prior to failure; (4) diagnostic code not captured at time of failure; (5) failure classification as 'normal wear' rather than manufacturing defect. One owner notes Kia claimed 'lifetime warranty' does not apply if no code captured, contradicting prior acknowledgment of fault. Dealers state they were 'gotten in trouble' for replacing too many engines and now require inspector approval (inspections only weekly). No extension to powertrain warranty offered beyond 100K–120K miles.
Spark Plug Fouling / Carbon Buildup
Spark plugs foul repeatedly due to oil burning into combustion chamber and carbon deposit accumulation. Plugs require replacement every 2–4 weeks or 300–1000 miles in severe cases. Carbon buildup clogs injectors and spark plug wells.
When: Occurs alongside oil consumption, typically 65K–118K miles; can begin shortly after purchase
Symptoms owners cite: Misfire (jerking/stuttering during acceleration); Check engine light, often with P0300–P0304 codes; Difficulty accelerating or loss of power; Engine runs rough, especially when starting; Black fouling residue visible on spark plug electrodes
Codes mentioned: P0300 (random misfire), P0301–P0304 (cylinder-specific misfire)
Repairs/costs cited: Spark plug replacement costs $50–$200 per set; owners report replacing plugs 4–7 times over 1–2 years. Dealers recommend combustion chamber/fuel injector cleaning ($350–$700). Owners cite repeated cleanings with no lasting fix. One owner changed spark plugs every 3 days due to fouling. Plugs often fouled within weeks of replacement.
Recalls/TSBs owners mention: Dealers recommend combustion chamber cleaning as diagnostic/corrective step (e.g., TSB 222 follow-up). Kia does not offer extended coverage for spark plug replacement or cleaning services. Owners expected to bear cost of repeated maintenance despite root cause (oil burning) remaining manufacturer-related.
Engine Knock Sensor Malfunction & Repeated Software Updates
Knock sensor fails to detect or correctly report engine bearing wear and misfire, or triggers false/intermittent warnings. Multiple knock sensor replacements and ECU reflash updates fail to resolve underlying bearing or misfire issues. Dealers replace knock sensors, perform BCT tests, and apply software updates (KSDS), but problems recur within days to months.
When: Reported at 36K to 111K miles; often after initial recall service
Symptoms owners cite: Check engine light flashing (knock detection); Engine light comes on and goes off intermittently; Vehicle enters limp mode despite sensor replacement; Engine knock sound persists after sensor replacement; Limp mode recurs within days to weeks of sensor replacement
Codes mentioned: P1326 (engine knock)
Repairs/costs cited: Knock sensor replacement cost $100–$300 (parts). ECU reflash (software update / KSDS update) performed at dealership, typically free under warranty. Multiple replacements of the same sensor cited in several complaints. Dealers acknowledge 'faulty' knock sensor in recall letters but subsequent failures indicate sensor is either not the root cause or vehicle has multiple defects.
Recalls/TSBs owners mention: KSDS software upgrade performed per recall notice (e.g., campaign PI1802B). Owners report being instructed to complete this update or risk warranty denial. After update, failures still occur. Kia also offers lifetime engine warranty contingent on (a) knock sensor replacement, or (b) completion of KSDS update. However, warranty is denied if knock code not present at time of failure or if owner did not receive recall notice (used car purchase without dealer notification). One owner reports Kia said 'the car would be ready that Saturday' and 'that was a lie,' with 5-week delay for full engine replacement and subsequent limp mode recurrence despite new engine installation.
Wiring Harness & Electrical Faults
Engine harness, knock sensor harness, or related wiring degrades or fails, triggering limp mode and check engine light. Multiple harness replacements do not resolve the underlying issue. Oil intrusion from failed engine damages ECU and engine harness electronics.
When: Reported at 36K to 111K miles; often after initial knock sensor replacement or KSDS update
Symptoms owners cite: Check engine light flashing, vehicle enters limp mode; Loss of power (capped at low RPM) or acceleration failure; Multiple visits to dealer with recurrence of limp mode
Codes mentioned: P1326 (engine knock, triggered by harness fault)
Repairs/costs cited: Wiring harness replacement attempted on multiple visits; one owner's vehicle required harness replacement 3+ times over 6 months (April–October 2019) with recurrence each time. One case cites oil intrusion from failed engine damaged injector harness and ECU, resulting in $6,000 estimate for harness, injector sub-harness, and ECU replacement.
Recalls/TSBs owners mention: Kia orders 'wrong wiring harness' in at least one case, requiring second replacement. Lifetime engine warranty denial cited if knock code not present. Oil damage to electronics after engine failure left customer with $6,000 out-of-warranty repair bill despite engine replacement being covered.
Misfire & Acceleration Loss Under Load
Engine misfires during acceleration or hill climbing, causing loss of power, jerking, and inability to maintain speed. Often occurs when accelerating from stop or merging on highway. No consistent warning lights initially; check engine light comes on only during or after failure.
When: Reported at 36K to 111K miles; often recurring over months
Symptoms owners cite: Loss of acceleration / inability to exceed 30–50 mph; Jerking and shuddering during acceleration; Engine feels like it is 'dying' or about to stall; Struggle going uphill; Check engine light illuminates during or after event
Codes mentioned: P0300 (random misfire), P0301–P0304 (cylinder-specific misfire)
Repairs/costs cited: Initial repair: knock sensor replacement. Follow-up: spark plug and ignition coil replacement. Further: combustion chamber cleaning ($350–$700). No permanent fix documented; owners report repeated misfire codes after each repair. One owner replaced spark plugs and ignition coils multiple times without resolution.
Recalls/TSBs owners mention: Dealers recommend knock sensor replacement and KSDS update per recall. Subsequent misfire codes treated as separate issues (spark plugs, injector cleaning) rather than symptom of underlying bearing/oil consumption defect. Warranty denied for repeat misfire/spark plug fouling if bearing lock code not present.
Limp Mode & Reduced Power (Drivability Hazard)
Vehicle enters limp mode unpredictably—RPM capped at 1,500–2,000, power severely reduced—forcing slow coasting or stopping in traffic. Can occur on highway at speed, creating hazard. Limp mode recurs after dealer 'fix' or persists despite multiple service visits.
When: Reported at 36K to 136K miles; often on highways or busy roads
Symptoms owners cite: RPM stuck below 2,000, unable to accelerate past 25–35 mph; Vehicle lurches or jerks into limp mode without warning; Check engine light flashing; Loud knocking or shaking if engine is straining; Loss of steering power assist in some cases
Codes mentioned: P1326, P0300–P0304
Repairs/costs cited: Multiple limp mode resets performed by dealers; one owner had vehicle in shop 3+ times (March–June 2019) for repeated limp mode. Knock sensor, wiring harness, and ECU updates attempted. No lasting resolution.
Recalls/TSBs owners mention: Kia assigns case manager to coordinate repairs. Repeated repairs authorized under warranty. However, permanent fix not achieved. One owner reports being told 'there is nothing they can do till it fails the BCT' despite engine already in failure state.
Rapid Engine Deterioration Post-Recall (KSDS Update)
Engine fails or accelerates deterioration shortly after KSDS software update completion, suggesting update may exacerbate or unmask existing defect.
When: Reported within weeks to months after KSDS update (February 2019, June 2021, etc.)
Symptoms owners cite: Engine failure or limp mode onset within 1–4 weeks of update; Loud knocking, loss of power, seizure
Codes mentioned: P1326
Repairs/costs cited: Full engine replacement required; one case resulted in 5-week wait for engine part and $19,040 lease buyout imposed on customer.
Recalls/TSBs owners mention: Kia acknowledges KSDS update is required to maintain warranty. However, failure post-update may not be covered if deemed 'unrelated' to update or if customer did not complete update prior to failure. One dealer required full engine replacement after update, creating liability dispute with Kia lease company.
Synthesized from 312 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 9 most recent
I had my car for about 2 years and it had 1 owner before me. At first it was a great car no issues, but soon it became a nightmare. First thing I noticed was my lights would turn off by themselves whiles driving at night. I usually kept them on auto and they would randomly go off and I would have to turn they nob off and back on to get them to come on again. Soon after that I noticed that I would…
The contact owns a 2016 Kia Optima. The contact stated that while driving at 20 MPH, the oil warning light illuminated. The contact veered to the side of the road and checked the oil level of the vehicle with the assistance of her son. The contact stated that her son noticed that the vehicle did not have oil on the dipstick. The vehicle was taken to Pep Boys who had previously refilled the oil…
Engine brocked the pistones brock stock engine and pay for new engine
Loss of power. Was driving across a 4 lane intersection and the vehicle lost power. The engine light came on. I stopped and check the oil and it was 2 quarts low. We had just changed oil less than 2,000 mikes ago. I tool the car to parts store and they said it was a p0309 code. That #4 cylinder misfire. It was either coil or spark plug. I replaced both coil and spark plugs 15,000 miles ago. The…
The contact owns a 2016 Kia Optima. The contact stated that while driving approximately 40 MPH, a knocking sound coming from the engine compartment was heard, and the check engine warning light illuminated. The contact further stated that while driving at approximately 80 MPH, with the cruise control mode engaged, the vehicle started to stall and failed to exceed 30 MPH. The contact stated that…
The contact owns a 2016 Kia Optima. The contact stated that the vehicle was consuming an excessive amount of engine oil. The oil level warning light was illuminated. The contact also noticed that the front driver's side tire was low. The vehicle was taken to the local dealer who informed her that the vehicle was 3-quarts low on engine oil due to the excessive oil consumption. The vehicle was not…
The contact owns a 2016 Kia Optima. The contact stated that while her husband was driving at an undisclosed speed, the vehicle lost motive power and stalled. The contact stated that the vehicle failed to restart. The vehicle was towed to the local mechanic who replaced the spark plugs and coil pack; however, the failure persisted. The cause of the failure was not yet determined. The local dealer…
My dealership has confirmed oil consumption on my vehicle
Had engine trouble with your 2016 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 2016 Kia Optima?
It's a documented issue but not catastrophic. 312 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 105 complaints that reported odometer mileage, most engine failures cluster between 70,000 and 111,000 miles, with the median around 92,500. A quarter of owners report trouble before 70,000; a quarter make it past 111,000. 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/2016/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.