2020 Kia Optima with 39,000 miles. Check engine light came on for knock sensor and put into limp mode. Before the check engine light came on I've been noticing a faint noise during acceleration from the engine. Waiting to hear back on the overall problem.
2020 Kia Optima engine problems
moderate 65 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
65
Recalls
0
Avg fix
$3,100
1crash
When does it fail?
Of the 65 engine complaints filed for the 2020 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 48% of every owner complaint on file for this vehicle — the dominant problem area across 5 categories tracked.
Owners have filed 65 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 2020 Kia Optima engine is at high risk of excessive oil consumption, internal bearing wear, and catastrophic failure—often before 100,000 miles—due to the same Theta II 2.4L GDI engine defect recalled for 2016–2019 models. The 2020 model year sits outside all recalls and class-action settlements, leaving owners responsible for engine-replacement costs exceeding $6,000–$10,000, with many dealers refusing warranty coverage and dealerships confirming these are known issues they cannot address.
Owners report the 2020 Kia Optima engine exhibits several interconnected failure modes. Excessive oil consumption is the most common complaint—many report burning 1–2 quarts weekly or requiring oil top-offs every 1,000–2,000 miles despite no visible leaks. Some describe blue smoke from the exhaust and fouled spark plugs covered in oil. This consumption often coincides with low oil pressure warnings that flicker during turns or idle and may fail to illuminate until pressure drops critically.
Engine stalling and limp-mode activation occur during highway driving at 60+ mph, with check engine lights flashing and dramatic power loss forcing vehicles to emergency shoulders. Multiple owners report the diagnostic code P1326 (knock sensor/bearing wear). Several describe metal contamination in oil and valve systems, metal shavings in the engine, faulty piston rings, and rod-bearing failure. Owners also report abnormal rattling, clanking, knocking sounds, sputtering, hesitation, and misfire codes (P0304).
A recurring complaint is that the 2020 model uses the same Theta II 2.4L GDI engine covered by recalls and class-action lawsuits for 2016–2019 models, yet the 2020 sits outside recall ranges. Owners note dealerships confirm these are "known issues" but deny warranty coverage, often citing mileage limits (60,000 for second owners) that are exceeded before failure manifests. One owner reported an oil drain plug that fell out at highway speeds. Another noted an oil-pan stress crack below the drain plug with no road damage evident.
Same Kia Optima engine reports on nearby years: 2017 · 2018 · 2019
Failure modes owners describe
Excessive oil consumption with fouled spark plugs
Engine burns 1–2 quarts of oil per week or requires top-offs every 1,000–2,000 miles despite no visible leaks. Spark plugs become covered in engine oil, causing misfires and sputtering. Blue smoke visible in exhaust. Oil light flickers during turns or idle, often failing to warn until pressure is critically low.
When: Begins 34,000–51,000 miles; reported at all mileages through 130,000+
Symptoms owners cite: Oil consumption 1–2 quarts per week or per 1,000–2,000 miles; Oil light flickering during turns, idle, or quick stops; Blue-tinted exhaust smoke; Fouled spark plugs covered in oil; Sputtering and hesitation during acceleration; Oil spots under parked vehicle
Repairs/costs cited: Valve cover replaced multiple times; spark plugs replaced repeatedly; oil consumption tests performed (some fail); mechanics recommend monitoring with top-offs every 1–3 months; one shop suggested engine flush as temporary measure; full engine replacement needed per multiple dealers
Recalls/TSBs owners mention: Dealerships note this is a 'known Kia issue' but decline warranty coverage citing mileage limits or vehicle age; some recommend monitoring and frequent top-offs rather than repair; no TSB or recall covering 2020 model year
Limp mode and power loss with P1326 code
Vehicle enters limp mode during highway driving (60–75 mph) with flashing check engine light, sudden loss of acceleration, and dramatic shaking. RPM cannot exceed 2,000–3,000. Diagnostic code P1326 indicates knock sensor or bearing wear. Often occurs without prior warning lights.
When: Reported at 45,000–138,000 miles; most incidents 80,000–120,000 miles
Symptoms owners cite: Sudden loss of engine power on highway at 60+ mph; Flashing check engine light; Vehicle shaking or shuddering; RPM stuck below 2,000–3,000; Cannot accelerate past 25–35 mph; Forced to emergency shoulder; Rattling or banging noise from engine
Codes mentioned: P1326
Repairs/costs cited: Mechanics retrieve P1326 and advise engine replacement; some note metal contamination in oil and valve systems; one owner paid for starter installation ($1,500+) before being told engine replacement not covered; repair costs exceed $6,000–$10,000; most vehicles not repaired
Recalls/TSBs owners mention: Dealers confirm this matches engine defect in 2016–2019 recall but state 2020 model not included; no warranty or campaign assistance offered; one dealer suggested engine might be covered under 'campaign' after starter repair but later denied coverage; no KRDS update offered to 2020 owners as provided to 2019 models
Rod bearing and internal engine damage
Engine develops metal contamination, faulty piston rings, rod bearing wear, and cylinder-wall scorching. Owners report metal shavings and debris in the oil system and on valve components. Some vehicles develop loud clanking or banging from the engine block, indicating imminent seizure. One oil drain plug fell out at highway speed, dumping all oil and causing loss of engine start.
When: Evidence of wear at 51,000+ miles; some noted during routine service; critical failure 69,000–127,000 miles
Symptoms owners cite: Loud banging or clanking from engine; Metal shavings or contamination in oil and on valve solenoids; Cylinder 4 misfire (P0304); Faulty piston rings; Engine seizure (vehicle immobile for months); Oil drain plug falls out; Engine will not crank after total oil loss
Codes mentioned: P0304
Repairs/costs cited: Mechanics recommend engine disassembly to check for wear; piston rings must be replaced; oil contamination requires system flush; full engine replacement required; one drain plug found in skid plate and replaced, but engine would not restart; one oil pan exhibited stress crack below drain plug with no impact damage; cost of replacement exceeds vehicle value for many owners
Recalls/TSBs owners mention: Dealerships note metal contamination confirms internal failure but offer no assistance; warranty expired for most; one dealer called for permission to install starter, mentioning possible 'campaign' coverage, then denied it after testing; manufacturer states issue not covered under any recall or campaign for 2020 model year
Oil-system and pressure failures
Oil pump failure, oil pan stress cracks, and drain-plug defects. One vehicle exhibited stress crack in oil pan below drain plug with no evidence of road damage; crack developed slowly and progressively worsened. Oil pressure warning light illuminates unreliably or only when pressure is extremely low, providing inadequate warning.
When: Oil pan stress crack developed progressively; oil pump failure at 167,000 miles; drain plug fell out 4,000 miles after routine oil change
Symptoms owners cite: Oil pan stress crack below and along both sides of drain plug; Oil drain plug falls out during highway driving; Massive oil loss (total drain); Low oil pressure warning light unreliable or delayed; Oil pump failure at low RPM and stationary idle
Repairs/costs cited: One owner replaced drain plug in field and refilled oil, but engine would not restart; required full engine inspection and likely replacement; oil pump failure caused low pressure while stationary; dealership found no report of drain-plug issue despite service-order documentation
Recalls/TSBs owners mention: One dealership lost vehicle for two weeks before finding it; another offered to perform test but owner declined, noting issue did not exist before servicing; no explanation provided; no technical bulletins issued for oil-pan or drain-plug defects
Oil-dipstick or fill-level discrepancy (1.6T model)
Owner of 1.6 Turbo model reports owner's manual specifies 4.75 quarts but vehicle reads full after 4 quarts and remains full after 250 more miles. Suspected owner's manual typo or incorrect dipstick installed during assembly. Concern raised that underfilling or overfilling could cause foaming and engine failure.
When: Discovered during routine oil service
Symptoms owners cite: Oil dipstick shows full after 4 quarts despite manual calling for 4.75 quarts; Discrepancy of 0.75 quarts unaccounted for
Repairs/costs cited: Owner used Fram filter (slightly smaller than OEM); no investigation performed
Recalls/TSBs owners mention: No known TSB or service bulletin addressing this; issue not investigated
Misfire and cylinder-specific failures
Engine develops misfires on specific cylinders (cylinder 4 reported) with check engine light illumination. Spark plugs become fouled by excessive oil and require replacement. Engine shakes and sputters during startup and acceleration.
When: Reported at 30,000+ miles; recurring after spark-plug replacement
Symptoms owners cite: Check engine light on or flashing; Misfire code (P0304 for cylinder 4); Sputtering and vibration during startup; Spark plugs fouled by oil; Shuddering while driving; Vehicle hesitation
Codes mentioned: P0304
Repairs/costs cited: Spark plugs replaced multiple times; fouling recurs within weeks; mechanic sealed two holes in oil pan but failure reoccurred; dealers recommended fuel-system cleaning and knock-sensor replacement; full engine replacement advised
Recalls/TSBs owners mention: Dealer informed owner warranty expired and engine replacement not covered; manufacturer advised filing NHTSA complaint; no additional assistance offered
Synthesized from 65 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 11 most recent
Took to Kia for engine burning excessive oil. They determined the cylinder wall was scorched due to piston ring. The warranty people say it’s normal wear and tear and won’t honor the warranty. It’s still sitting in their engine bay because they want me to pay for the diagnostic which I don’t have. $4000 roughly for that but it needs a new engine. The warranty should be covering this! NEVER…
The contact owns a 2020 Kia Optima. The contact stated while driving 30 MPH, the vehicle went into LIMP Mode. There was no warning light illuminated. The vehicle was taken to an independent mechanic, who diagnosed that the engine consumed an excessive amount of oil and determined that the engine needed to be replaced. The vehicle was then taken to the dealer, where it was diagnosed that the…
Vechile is burning oil and knock sensor came on which indicated rod bearing. While driving the car lost power the check engine came on was abl to pull over and turned off the car. Did not drive it was tow home.
I got the car was running good week or 2 later I see the oil light flash after my oil change I go back top it off repeat the cycle almost weekly burning losts of oil then I get a code p1326 for a knock sensor same day car go into limp mode no power rpm won’t go over 2 car won’t go over 60-65 I park it go outside to take it to the dealership next day it ain’t start I haven’t had the car 4 months…
It is an oil burner and engine failed and went into limp mode less than 5 years when drove off dealership brand new.
The contact owns a 2020 Kia Optima. The contact stated that the vehicle was consuming an excessive amount of engine oil. The contact stated that oil changes needed to be performed more frequently than normal. The contact stated that the oil light remained illuminated. The local dealer was not contacted. The vehicle was not repaired. The manufacturer was not notified of the failure. The…
Driving at highway speed of 65 mph, the vehicle abruptly lost power. The check engine light started flashing. I was almost rear ended due to the loss of power, I was able to coast to the emergency shoulder and stop. The car was towed to the nearest Kia dealership. Diagnostics show code P1326, the engine has failed and needs to be replaced at a cost of over $10000. This the same engine that…
Oil plug fall out at highway speeds, engine failure. Engine stalled while driving, got vehicle to side of road, called tow truck after attempting to restart. When tow truck driver pulled vehicle onto the flatbed a massive amount of oil came out. After driver towed vehicle home he looked for a hole in the block found where plug had fallen out and advised us to look in the skid plate to see if oil…
Vehicle was tampered before purchasing, transmission mounts broken, evap hose gas tank and engine.. car was claimed as a lemon vehicle, dealership sold me a vehicle that’s unsafe to operate. Dealership refuses to fix…
Had engine trouble with your 2020 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 2020 Kia Optima?
It's a documented issue but not catastrophic. 65 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 69,751 and 123,000 miles, with the median around 116,000. A quarter of owners report trouble before 69,751; a quarter make it past 123,000. 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/2020/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.