2018 Kia Optima engine and engine cooling problems
14 owner complaints filed with NHTSA name the engine and engine cooling on the 2018 Kia Optima — 6% of all complaints for this model year.
What owners report
“The contact owns a 2018 Kia Optima. The contact stated that while driving at an undisclosed speed, there was an abnormal odor and a knocking sound coming from the engine. The vehicle was taken to the dealer; however, the dealer was unable to duplicate the issue. The vehicle was not repaired. The…”
filed Jun 23, 2026
“The contact owns a 2018 Kia Optima. The contact stated that while attempting to accelerate from a standing start the vehicle had experience sever jerking and hesitation. Also, the vehicle has experience oil consumption problems and the contact constantly added engine oil. The cause of the failures…”
filed May 6, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Engine and Engine Cooling problems in other Optima years
| Year | Reports | Share |
|---|---|---|
| 2020 Optima | 8 | 6% |
| 2019 Optima | 3 | 1% |
| 2017 Optima | 7 | 3% |
| 2016 Optima | 24 | 3% |
| 2015 Optima | 30 | 3% |
| 2014 Optima | 14 | 2% |
| 2013 Optima | 41 | 3% |
| 2012 Optima | 19 | 2% |
| 2011 Optima | 7 | 1% |
| 2010 Optima | 2 | 3% |
| 2009 Optima | 2 | 2% |
| 2008 Optima | 5 | 3% |
Other reported problem areas on the 2018 Kia Optima
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.