About this problem
Engine failure complaints describe engines that knock, seize or stop running entirely, often with a sudden loss of power on the road. The usual mechanical cause is wear in the connecting rod bearings, which can follow from manufacturing debris, low oil or oil starvation. Once a bearing fails, the engine usually needs to be replaced. Some failures on these engines are covered by recalls or extended warranties.
Across all owner complaints filed about the Kia Optima since 2012, 1,452 (25%) describe engine knocking and failure, making it the most reported problem we track on the Optima. The reports cluster on the 2012, 2013 and 2015 model years, and the 2015 drew the most, with 336. It tends to show up at higher mileage: half of the owners who gave a mileage were between 71,000 and 125,000 miles. 87 reports describe a crash or fire linked to it. 3 recalls are related to it, and recall repairs are free at any dealer.
What owners report
Owners of 2011 to 2015 Optimas report knocking, stalling, loss of power and engines that seized, with many fire reports. These engines share Hyundai's Theta II design and are covered by Kia's engine recalls and warranty extension. The 2012, 2013 and 2015 cars drew the most reports.
How it gets fixed
Kia replaces failed engines under recall or warranty extension and installs knock sensor software that warns of bearing wear.
Typical cost: Free if covered. Otherwise a replacement engine costs $4,000 to $7,000.
Complaints by model year
In owners' words
"Regarding to the previous complaint, veh was taken to dealer on 3/15/2013 to adjust the alignment under warranty due to the alignment issue starting after the engine was replaced at 3,400 by the dealer."
2013 Kia Optima, 3,400 miles
"I recently started hearing a knocking noise coming form the engine when accelerating. I work at Lexus of austin and had the car diagnosed. They determined that the engine was suffering from a connection rod failure."
2012 Kia Optima, 71,000 miles
"Nearing 60,000 miles, the car started to make a weird engine noise. The Kia dealership found that the connecting rod was bad and the engine needed replaced. This issue is very well know and widespread."
2015 Kia Optima, 59,000 miles
Excerpts from public owner complaints filed with the National Highway Traffic Safety Administration, lightly trimmed.
Related recalls
Kia Motors America (Kia) is recalling certain 2011-2017 Optima, 2012-2017 Sorento and 2011-2018 Sportage vehicles that previously received an engine replacement under recall number 17V-224, warranty, or the Knock Sensor Detection System (KSDS) Product Improvement Campaign.
Kia Motor Company (Kia) is recalling certain 2011-2014 Optima, 2012-2014 Sorento and 2011-2013 Sportage vehicles.
Kia Motors America (Kia) is recalling certain 2017-2018 Optima Hybrid and Optima Plug-In Hybrid vehicles.
Recall repairs are free at any dealer. Check a specific car by VIN at nhtsa.gov/recalls.
Service bulletins and warranty extensions
Kia has sent dealers 112 bulletins that mention this problem on the Optima. A bulletin tells technicians how to fix a known fault. It is not a recall, so the repair is usually free only while the car is under warranty or covered by an extension.
Warranty bulletin: wty004 - 2011-2014 my Optima (tf/qf) engine short block warranty extension (wty004) - this warranty bulletin provides information related to the extension of the new vehicle limited warranty for the engine sh...
Dealer parts and service manager memo: wty004 - effective immediately, Kia motors america, inc.
Owner letter: wty004 - dear Kia Optima owner: Kia motors america takes pride in providing you with high quality and dependable vehicles.
CUSTOMER SATISFACTION BULLETIN: 2017-01 - 2014 MY Optima (TF) ENGINE SHORT BLOCK WARRANTY EXTENSION - The purpose of this bulletin is to provide information related to the extension of the New Vehicle Limited Warranty for the E...
PRODUCT IMPROVEMENT CAMPAIGN: DEALER PRINCIPAL MEMO - This document is the announcement to the dealer principals that Kia is conducting a Product Improvement Campaign to perform a software update to the Engine Control Unit (ECU...
PRODUCT IMPROVEMENT CAMPAIGN: DEALER PARTS AND SERVICE MANAGER MEMO - This document is the announcement to the dealer Parts and Service Managers that Kia is conducting a Product Improvement Campaign to perform a software update...
Government investigations
Defect petition DP18003 · 2012–2014 · opened Aug 2018, closed May 2019
Engineering analysis EA21003 · 2012, 2013, 2014, 2017, 2018 · opened Dec 2021, closed Feb 2024
Preliminary evaluation PE19004 · 2012–2014 · opened Mar 2019, closed Dec 2021
Before you buy a Optima
- Ask for oil change records; long gaps are a red flag on these engines.
- Listen for knocking or ticking at idle and when accelerating.
- Check by VIN for open engine recalls and for any extended engine warranty.
Questions
Which Kia Optima years have engine knocking and failure?
Complaints are highest for the 2012, 2013, 2015 model years. The 2015 drew the most, with 336 reports.
At what mileage does it usually start?
Among owners who gave a mileage, the middle figure was about 99,000 miles, and half reported it between 71,000 and 125,000 miles.
How much does it cost to fix?
Free if covered. Otherwise a replacement engine costs $4,000 to $7,000.