2015 Kia Optima Engine cooling Problems
- Complaints
- 31about this part
- Share
- 3%of 1,010 total for the year
- Median mileage
- 100,794miles
- Trend
- RisingComplaints filed in the last 3 full calendar years are at least 25% higher than in the 3 years before.
NHTSA recorded 31 complaints about the engine cooling of the 2015 Kia Optima, 3% of the 1,010 complaints for this model year. Where a mileage was given, the median is 100,794 miles. 2 of these say a crash was involved and 5 a fire, according to the filers.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“My vehicle engine blew while driving on the highway going about 65 no warning or signs other then the amount of oil that it was consuming. I am just now hearing about the class action lawsuits for my specific engine the Theta 2.0 which I have already verified it is part of it. KIA is saying it's the wrong part of the engine that is blown that it want be qualify for the engine replacement. …”
NHTSA complaint #11497491, filed 2022-12“Driving on highway 54 all of a sudden vehicle seized up on me at 75 mph in the dead of night, steering was difficult to control and hit an object while trying to stop off the highway IN A BLIND CURVE! Was stranded for 6 hours until local shop towed vehicle and replaced condenser-radiator-fan ( object was debris on side of highway) could not get car going and a smell of electrical short coming from under hood. Have not been able to fix problem and have spent 11 days in Carrizozo NM trying with bewildered mechanics to get me back on the road. …”
NHTSA complaint #11459953, filed 2022-04“The contact owns a 2015 Kia Optima. The contact stated that while driving at 40 MPH, there was smoke coming from underneath the hood, and the engine overheated. The check engine warning light was illuminated. The contact was able to pull over to the side of the road and add coolant to the coolant reservoir. The vehicle slowly started and was driven to the destination. The contact stated that the engine was overheating if driven for more than 10 minutes. …”
NHTSA complaint #11721647, filed 2026-03, 124,000 miles“The contact owns a 2015 Kia Optima. The contact stated while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. Additionally, the check engine warning light illuminated, and the vehicle turned off unintendedly. The vehicle was towed to the dealer where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. …”
NHTSA complaint #11609618, filed 2024-08, 92,394 miles“The contact owns a 2015 Kia Optima. The contact stated that while operating the vehicle, there was a knocking sound coming from the engine compartment. After stopping at a red light, the engine suddenly failed. The vehicle was towed to the local dealer who diagnosed that the engine was faulty and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure, but no assistance was offered. The failure mileage was 88,000.”
NHTSA complaint #11505324, filed 2023-02, 88,000 milesRelated service bulletins
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Engine cooling: other model years
| Year | Complaints | Share of year |
|---|---|---|
| 2020 | 8 | 5% |
| 2019 | 3 | 1% |
| 2018 | 14 | 6% |
| 2017 | 8 | 3% |
| 2016 | 24 | 3% |
| 2015 | 31 | 3% |
| 2014 | 16 | 3% |
| 2013 | 42 | 3% |
| 2012 | 20 | 2% |
| 2011 | 8 | 1% |
| 2010 | 2 | 3% |
| 2009 | 2 | 2% |
| 2008 | 5 | 3% |
| 2007 | 4 | 2% |
| 2006 | 9 | 6% |
| 2005 | 6 | 4% |
| 2004 | 11 | 5% |
| 2003 | 7 | 5% |
| 2002 | 7 | 7% |
| 2001 | 24 | 17% |
Other parts of the 2015 Kia Optima
623 complaintsOther or unknown
140 complaintsElectrical system
135 complaintsBrakes
90 complaintsBody and structure
76 complaintsSteering
69 complaintsFuel system
56 complaintsTransmission and drivetrain
49 complaintsVehicle speed control
36 complaintsAir bags
26 complaintsExterior lighting
23 complaintsElectronic stability control
10 complaints
← All problems reported for the 2015 Kia Optima
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 27, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology