Which parts fail
Components named in complaints (fuel pump, injectors, fuel tank, hybrid and EV propulsion).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2016 Kia Optima owners, lightly cleaned up (personal details are redacted by NHTSA).
While driving, the vehicle suddenly developed a loud knocking noise from the engine. Within one block the vehicle began smoking heavily from under the hood. I pulled over, opened the hood, and flames were visible. This is a 2016 Kia Optima with the 2.4L Theta II engine. Approximately one year ago the original engine seized and was replaced by a Kia dealer under the Theta II engine recall (SC172/SC147) and class-action settlement. This is the second catastrophic failure of a Theta II engine in this vehicle. The replacement engine has now failed in the exact same manner as the thousands of other documented cases - rod bearing failure leading to knocking, overheating, and engine compartment fire. …
The contact owns a 2016 Kia Optima. The contact stated while driving 65 MPH, the check engine warning light illuminated and the vehicle stalled. The contact was able to veer to the side of the road. The contact was unable to restart the vehicle after several attempts. The contact also stated that she smelled an abnormal gasoline odor. The vehicle was taken to the dealer where it was diagnosed that an engine cylinder had failed. The dealer informed the contact that the vehicle could not repair under NHTSA Campaign Number: 18V907000 (Fuel System, Gasoline, Engine) unless the engine was knocking. The vehicle was not repaired. The contact stated that the engine was misfiring while driving and the vehicle would not exceed 40 MPH. The vehicle was taken back to the dealer where it was diagnosed that the engine was misfiring and oil was leaking onto the spark plugs. …
The contact owns a 2016 Kia Optima. The contact stated while driving at various speeds on several occasions, the vehicle was shuddering with a knocking sound coming from the engine compartment. The vehicle was taken to a dealer where it was diagnosed and determined that the engine needed to be replaced. The vehicle was repaired; however, the failure persisted. The contact stated that a message "Do not drive - Tow to Dealer" was displayed, and the check engine warning light was illuminated. The vehicle was towed to the dealer where it was diagnosed that a loosened turbo hose needed to be tightened. The vehicle was repaired but the failure persisted. The vehicle was towed to another dealer where it was diagnosed that the high-pressure fuel pump needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 112,000.
The contact owns a 2016 Kia Optima. The contact stated upon activating the heater while driving, she smelled an abnormally strong gasoline odor. There was no warning light illuminated. The contact related the failure to Kia Independent Recall Campaign Number SC172 (High Pressure Fuel Pump Outlet Inspection). Additionally, the contact stated while driving and depressing the accelerator pedal, the vehicle hesitated to respond and then lunged forward abruptly. There was no warning light illuminated. The contact stated that the failure had been reoccurring while driving. The dealer and the manufacturer were notified of the failure and informed the contact that she needed to pay for a diagnostic test and the repair cost because the VIN was not included in any recalls. The vehicle was not diagnosed or repaired. The failure mileage was approximately 110,000.
5/9/23 appointment for 4 recalls -completed 2 and ask if we could bring back next day to finish and we said no because granddaughter in school so service manager said important to get it back in and finish and sent granddaughter home with car 5 days later while driving car caught on fire and lost brakes and transmission and swerved into vacant parking lot smoke and flames coming into car and girls had to jump while car was still moving both girls checked on sight for smoke inhalation. 15 year old had to go to emergency room for road rash and nerve issues. we have documents ,911 tapes, videos, text ,,,witnesses, pictures. very negligent on service dept. for sending car out without completing issues. we came ready to leave it but they sent it out.
The contact owns a 2016 Kia Optima. The contact stated while driving at an undisclosed speed, the vehicle inadvertently lost motive power. The driver was able to pull over to the shoulder of the roadway, where the vehicle failed to restart. The check engine warning light was illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the fuel pipe and determined that the fuel pipe was leaking into the engine. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 18V907000 (Fuel System, Gasoline, Engine); but the VIN was not included. The manufacturer was not notified of the failure. The failure mileage was 68,000.
The contact owns a 2016 Kia Optima. The contact stated that while driving at 60 MPH, the vehicle stalled with the check engine light illuminated. The brake pedal was depressed, and the steering wheel seized. The contact was able to pull over to the side of the highway and contacted the Highway Patrol for assistance. The contact associated NHTSA Campaign Number: 18V907000 (FUEL SYSTEM, GASOLINE, ENGINE); with the failure; however, the VIN was not included in the recall. The vehicle was towed to the residence. The dealer was not notified. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 105,000.
I was told that my engine had a recall on it so I had an upcoming appointment with Kia in like 2 weeks for them to check my engine but the car didn't make it. I was driving my car on interstate 20 my car had began to have a bad chemical smell and started smoking so I pulled over on the interstate and my car was in flames. Me and my daughter was in the car we could have lost our lives thank God we were able to make it out just in time. The fire department came and made a report on the incident. It wasn't any engine light on at the time. I have contacted Kia about the tragedy that has happened but nothing has been resolved yet.
It started shaking really bad out of no where , then wasn't going faster than 80 then down to 65 but wouldn't go more than 80 with my foot all the way on the gas. As soon as I made it to work tonight the car cut off. I got a jump the car was still shaking & wouldn't stay on if I let my foot off of the gas. I started it again without the cables but it cut right back off. I saw on cars.com it's a recall for the similar thing, number Sc172. I have been having fuel leaks for a while and had my knock sensor replaced from a previous recall. Now I have no way home.
The contact owns a 2016 Kia Optima. The contact stated that while driving at an undisclosed speed, the vehicle lost motive power with an unknown warning light illuminated. Additionally, the vehicle occasionally overheated while the coolant level was full. The dealer was made aware of the failure; however, the vehicle was not diagnosed nor repaired. The contact related the failure to a faulty low-pressure fuel pump. The manufacturer was made aware of the failure. The failure mileage was approximately 47,000.
Fuel System complaints in other Optima years
Frequently asked questions
How common are fuel system problems on the 2016 Kia Optima?
NHTSA has 63 complaints about the fuel & propulsion system of the 2016 Kia Optima, 8% of the model year's 759 complaints. The component named most often is delivery › fuel pump (2 mentions).
Is there a recall for 2016 Kia Optima fuel system problems?
No. NHTSA lists no fuel & propulsion system recall for the 2016 Kia Optima, though it has 5 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2016 Kia Optima fuel system problems start?
Half of the complaints with a recorded mileage happened before about 75,000 miles, and 10% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 6 fires and 1 injury to fuel & propulsion system problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.