2015 Kia Optima · symptom sheet
Engine failure, knocking or rod bearing
- 319owner reports
- 88,000median miles
- $5,500median quote
- 4involved a crash
Newest report Sep 20, 2026 · checked Oct 2, 2026
647 of the 1,006 complaints on this car are about the engine. 319 of those describe engine failure, which makes it the most reported problem on the 2015 Optima.
Narrower sheets: Engine knocking or ticking (118 reports) · Engine seized (92 reports) · Rod bearing failure (27 reports)
Tick what matches of 319 reports
Engine failure on other Optima years
Report counts are for each model year on its own, so a newer car has had less time to collect them.
What this problem usually is
These are the reports nobody wants to file. The engine started knocking or ticking, the oil light came on, and then it seized or had to be replaced. Some owners had the replacement covered under warranty or an extension, and plenty were told they'd pay. Several narrower sheets split this group into knocking, seized engines and rod bearing failure.
What got replaced
Owners who name the part that was replaced mention the engine (303 reports), the turbo (7 reports) and the timing chain (3 reports).
Recalls and investigations
No recall on the engine covers the 2015 model year as of Oct 2, 2026.
NHTSA investigations into the engine on the Optima
Loss of motive power. Closed dec 12, 2023.
Engine fires. Closed feb 5, 2024, led to recall 23V-877.
Scope and timeliness. Closed dec 22, 2021, led to recall 17V-224.
What owners paid
31 of the 319 reports quote a price. Each dot is one quote. The middle half runs $1,522 to $7,000.
When it happens
The middle half of failures fell between 63,523 and 116,000 miles, from the 196 reports that gave a mileage.
Is this a known problem?
The manufacturer has sent NHTSA 22 service bulletins or notices for the 2015 Kia Optima that deal with this problem. Newest first.
Federal rules make a manufacturer send NHTSA a copy of any notice about a defect that goes to more than one dealer or owner. Most of these are service bulletins, the repair instructions manufacturers send to dealers. NHTSA generally leaves safety recall bulletins out of this file, and recalls are listed separately.
PRODUCT IMPROVEMENT CAMPAIGN: ENGINE REPLACEMENT INSTRUCTIONS FOR DTC P1326 (PI1802Y/Z) This bulletin provides information related to the Technical Service Bulletin previously published PI1802 titled "Knock Sensor Detection System - ECU Logic Improvement"; equipped w/THETA II engine.
PITSTOP: INJECTOR HARNESS ROUTING FOR PI1802Y/Z AND PI1803Y/Z ENGINE REPLACEMENTS This bulletin provides information to address a no-start or hard start with poor running condition after engine replacement under PI1802Y/Z or PI1803Y/Z. Some replacement long blocks may come with pre-installed fuel rail, injectors, and injector wiring ...
ENGINE REPLACEMENT INSTRUCTIONS FOR DTC P1326 (PI1802Y/Z) This bulletin provides information related to the Technical Service Bulletin previously published PI1802 titled "Knock Sensor Detection System - ECU Logic Improvement" equipped w/THETA II engine.
PRODUCT IMPROVEMENT TSB_PI1802_R2 - Knock Sensor Detection System - ECU Logic Improvement - This bulletin provides information related to a software update to the Engine Control Unit (ECU) to install the Knock Sensor Detection System (KSDS) in order to protect the engine from ...
18 more on the 2015 Kia Optima page.
What owners wrote
“My energy in my car started messing up with only 150,000 miles it had a long knocking sound and it would not got over 20 miles while driving”
Filed Sep 20, 2026 · 150,000 miles
“The engine had less than 40K miles on it and a total engine failure occurred due to blown head gasket. They replaced the engine with another used engine and this one started smoking and nearly caught on fire, resulting in another total engine failure. They are now trying to install an engine with an unknown amount of mileage on it as the replacement engine.”
Filed Jan 18, 2024 · 40,000 miles
“2015 Kia Optima engine seized on the highway at 70mph without any warning. Engine light illuminated and lost all power. This was a replacement engine with approximately 75,000 miles. Original engine was replaced at 125k due to excessive oil consumption (burned 1 quart in 800 miles). Vehicle has been at the dealership since the end of June awaiting engine replacement (again).”
Filed Aug 9, 2023 · 75,000 miles
“Driving down Interstate and car stopped with no warning. It was confirmed engine seized at 113,576 miles.”
Filed Jul 20, 2023 · 113,576 miles
Should you keep driving it?
This page can't tell you that. 4 of 319 reports involved a crash and 3 people were hurt. Owners who file are the ones who had a bad experience, and nobody checks their reports. If the problem affects steering, braking, power or a fire risk, treat it as a safety fault and have it inspected before a long or high-speed drive.
File your own report with NHTSA. Complaint counts are how a problem gets an investigation. How reports land on this sheet.
Guide Taking it to a shop? How to describe this problem so it gets found
Other problems on this car
- Engine stalls or loses power while driving 256 reports
- Check engine light or misfire 108 reports
- Brakes grind, pulse or wear early 89 reports
- Vehicle fire 70 reports
- Paint peels or body rusts 56 reports
- Engine rattles or ticks 49 reports
- Burns oil or oil level rises 37 reports
- Battery dies or the car will not start 30 reports
- Airbag warning light or recall 26 reports