10.0

really awful
Crashes / Fires:
1 / 2
Injuries / Deaths:
0 / 0
Average Mileage:
8,862 miles

About These NHTSA Complaints:

The NHTSA is the US gov't agency tasked with vehicle safety. Complaints can be spread across multiple & redundant categories, & are not organized by problem. See the Back button — blue bar at the very top of the page — to explore more.

Get notified about new defects, investigations, recalls & lawsuits for the 2018 Hyundai Sonata:

Unsubscribe any time. We don't sell/share your email.

problem #51

Jan 152024

Sonata

  • miles
-?? In early 2024, I brought my vehicle to a Hyundai dealership due to rapid oil loss. I reported having to refill the oil weekly and suspected a leak. They diagnosed a cracked oil pan, claimed to fix it, and returned the car. However, immediately after, the car continued burning oil at an alarming rate. I was forced to buy and add oil every single week, spending hundreds of dollars to maintain drivability. Shortly after the repair, I began experiencing erratic dashboard warnings. The check engine light would frequently come on and off. The oil lamp illuminated every few days. These symptoms were persistent, not isolated incidents. Despite reporting the issue again, I was told the oil burning was -??normal-?? for Hyundai engines and nothing to worry about. That response put my safety and my child-??s safety at risk, as I was unknowingly driving a vehicle with worsening engine damage. Eventually, the car stopped running entirely. It was no longer drivable or safe. I took it to a licensed independent mechanic who confirmed there were multiple ongoing oil leaks and extensive engine damage. The issues I originally reported were never properly fixed, and it-??s now clear the dealership failed to address the root cause of the oil consumption problem. I also noticed unusual spikes in the odometer after their repair, despite working from home and barely driving. This added further concern that the vehicle-??s internal systems may have been compromised or malfunctioning. I believe Hyundai-??s failure to act on clear warning signs directly led to this total engine failure and a serious safety risk.

- Camden, SC, USA

problem #50

May 232025

Sonata

  • miles
Multiple critical mechanical and safety issues have occurred with my 2018 Hyundai Sonata Sport. The vehicle has experienced persistent engine misfire, a severe oil leak, emissions system failure, and extensive paint deterioration. A certified technician confirmed an active oil pan leak with no dashboard warning lights, posing a fire and stalling hazard. To prevent further damage, I replaced the entire oil pan and spark plugs at a personal cost of approximately $800 at Firestone Complete Auto Care. The check engine light revealed diagnostic code P0420 -?" Catalyst System Efficiency Below Threshold (Bank 1). An O-??Reilly emissions scan confirmed the catalytic converter failure, and emissions status was marked -??RED.-?? The vehicle will not pass an OBD-based emissions test. At 149,219 miles, Hyundai refused warranty coverage due to mileage. A certified Hyundai dealership quoted $3,722 to replace both the catalytic converter and valve cover gasket, which remains unaffordable and unrepaired. In addition, the factory-applied white paint began peeling severely from the hood and roof. Although Hyundai issued a warranty extension for this known defect, the dealership refused to repaint the hood, citing a minor dent -?" even though the peeling is clearly unrelated. The exposed metal has started to rust, risking structural deterioration. All concerns have been evaluated by certified Hyundai service and independent professionals. These combined mechanical, emissions, and exterior failures raise serious safety and durability concerns. I am filing this report to document manufacturer-related defects that may affect other owners of this model and year.

- Springfield, MO, USA

problem #49

May 082025

Sonata

  • miles
I have to put a quart of oil in every week. It burns oil.

- Springfield, MO, USA

problem #48

May 062025

Sonata

  • miles
Panoramic sunroof came loose on highway and bent up 90 degrees making vehicle undrivable.

- Davie, FL, USA

problem #47

Oct 042024

Sonata

  • miles
When I bought the car from Mathews in Marion Ohio the car looked like it was already in some form of accident due to a previous owner and I was unaware what caused the accident or any other problems with the vehicle upon buying. I was not presented with a carfax. I have electrical tape at the bottom of my bumper and there-??s a problem with acceleration. It accelerates by itself and veers right when I take my hand off the wheel. I-??m afraid to drive my car on the highway. I have complained about this problem to Mathews twice. I am now in a loaner until they figure out what-??s going on.

- Marion, OH, USA

problem #46

Mar 042021

Sonata

  • miles
I looked up my car on carfax and it shows a 3 different odometer readings. on 10/14/19 it had 15.125 miles. On 03/04/21 it had 61,284 miles. On 02/01/2022 it had 30,371 miles And finally on 3/3/23 it had 38,269 miles. This clearly shows that somewhere along the line, the odometer was changed. My car has been on the shop on several occasions in the less than 2 year time frame

- Baltimore, MD, USA

problem #45

Nov 012024

Sonata

  • miles
43000 miles on car. original owner. new battery. car does not cold start in the morning. all electronics light up, but engine doesn't start. This is a known issue from all the posts i found online, yet Hyundai has not issued a recall. I paid 300 for a battery 2 weeks ago and the issue didn't resolve. Now i am being told by dealer it is the starter and it's not covered because my 5 yr warranty is expired (my car is 6 years old). This is a known safety issue across the 2018 Sonata line. This should be a recall or bulletin, instead I have to come up with hundreds of dollars more to replace a starter on a car with ONLY 43,000 miles.

- Knoxville, TN, USA

problem #44

Sep 182024

Sonata

  • miles
My 2018 Hyundai sonata with only 20,821 had to have the starter replaced on [XXX] because the car would not start. I had 3 different people including AAA road service to verify why it would not start and what the problem was. I end up having my car towed with AAA to a local mechanic shop, Mike Hepler auto repair St. Cloud Florida 34769 407-593-0152, and Mike did the diagnosis saying the starter was bad it was(fried) as he put it. He said he could replace it for $492.17 for part and labor which I accepted for him to do the job. I had left numerous messages (4)for my local Hyundai dealership service department to call me to let get a diagnosis and no one has ever called me back to give them my information or ask any questions.

- Kissimmee, FL, USA

problem #43

Dec 152023

Sonata

  • miles
The paint if pealing off in large sections due to a manufacturer defect in the primer. The flakes can fly onto the windshields of other vehicles causing collisions.

- Cleveland , TN, USA

problem #42

Oct 202023

Sonata

  • miles
For now the fifth time in the last 16 months the HEV light and engine light has lit up while the car jerks and sputters and dies. Below is the incident report that I filed on or about August 8, 2022. Again at the end of the day yesterday on October 20, 2023 the same issues still arise for the fifth time. See below for a re-cap of the issues I am once again experiencing after Hyundai claims to have fixed the issues: For the fourth time the HEV light (and others) has come on and the dash has lit up while I was driving, with the last three times leaving us stranded in dangerous road situations with little or no power. The light first came on in July 2020 at 40,089 miles. A dealership reset the codes and I had no problems until June 7, 2022 when the lights lit up on the dash again and the car died and I had to have it towed to a local dealership. They could find nothing wrong with it and checked all the wiring and said none of the codes were coming up and that the car ran fine for them when test driving a day or two after I had it towed. So they released the car back to me deeming it good to go. Then only 19 days later on June 26, 2022 the HEV light among other lit up again and the dash indicated to pull over and cut the car off due to the hybrid system. I had it towed to the nearest dealership again. The then looked at it and said they reset all the codes and everything looked to be good to go. Then AGAIN on Aug 8, 2022 (3rd time in two months), we were put in a dangerous situation trying to get the car off a busy highway when the HEV light (and others) again lit up the dash and our power went almost completely out while the engine jerked violently as we tried to avoid being hit by cars while trying to get off the highway before it completely died on us. Four times now Hyundai dealers have shrugged this off saying "we reset the codes" and we can't find an issue. We have been put in dangerous traffic conditions three of these times.

- Keller, TX, USA

problem #41

Aug 052023

Sonata

  • miles
UNKNOWN. I noticed that there was a check engine light on and I took it to autozone to have it checked out, they told me that it was coming back with the code of an o2 sensor. I thought nothing of it until it started not wanting to start right. On July 1, 2023 I took my car in to the dealership for an oil change and they never said anything about why my car was doing a delayed start. It would eventually start but it took at least a minute. I bought a new battery from walmart to put in my car so that it would not do the delayed start, but it kept doing it anyway. Finally decided to take it to a mechanic and the first time that he started it took at least a minute, he realized that he didn't have his computer (code reader) with him so he turned it off. When he returned with the code reader he plugged it in and started the car then it started smoking, smoking turned into fire that caused the entire underside of my hood to melt including engine, electrical harness, belts, battery and much more. If it wasn't for the mechanic's quick thinking by putting out the fire while calling 9-1-1, the fire would have gone to the fuel tank and exploded. Yes, the safety of others was put at risk.

- Bella Vista, AR, USA

problem #40

May 282022

Sonata

  • miles
This vehicle consumes one quart of oil every 1000 miles. I have documentation to prove it. Hyundai has done their own asessments and claimed that it consumes less. There was a class action lawsuit filed in California for this issue.

- Buffalo Grove, IL, USA

problem #39

May 232023

Sonata

  • miles
When driving the car on the highway - "check engine - hybrid system" warning lights come on and indicate hybrid system issue and to shut car off immediately. Extreme safety issue as the car goes from highway speeds to 35MPH almost instantly. This has happened seven times now and Hyundai keeps indicating that technicians are following engineering guidance in fixing the issue related to the knock sensor. The seventh occurrence happened on May 23rd of 2023. First one was in December 2021. As Hyundai is unable to correctly fix the issue I have repeatedly asked for them to replace the car since it is an extreme safety issue but they will not do so. Still waiting for diagnosis of the latest occurrence from May 23rd. Hyundai does not acknowledge that this issue is of safety concern and just indicates that the issue has been fixed each time it occurs.

- Westerville, OH, USA

problem #38

Mar 032022

Sonata

  • 111,325 miles
During the drive, check engine lights on then suddenly, HEV warning lights with turn off the engine with critical alert sound. I was drove again after attempting to start several times then again & again... It freaked me out when I drove on the highway, and yet to fixed & afraid to go to the dealer becase of cost & uncertain reasons. This could be big accidents on the highway.

- Englewood, NJ, USA

problem #37

Dec 312022

Sonata

  • miles
Hyundai boosted about their emergency response system included with my vehicle and charged extra. They failed to tell me that they were discontinuing the system. If I crash and need assistance bc I'm unconscious, I won't get it.

- Lewisburg, TN, USA

problem #36

Sep 142022

Sonata

  • miles
The White paint is peeling off the vehicle.

- Babylon, NY, USA

problem #35

Jan 232023

Sonata

  • miles
2018 Sonata has white paint peeling on hood of car - only 29,930 miles on car

- Norwood , NJ, USA

problem #34

Oct 122022

Sonata

  • miles
2018 Hyundai Sonata Sport+ with 23K miles that has White Pearl exterior paint. The paint (W8 or WW8) is peeling off from several locations (Hood and Roof). This has been a know issue with this type of paint on Hyundai vehicles but manufacturer is not taking any responsibility that paint or paint job is defective. One can google this issue and thousands of user complaints are there of different forums and messaging boards. Example: https://community.cartalk.com/t/2018-hyundai-sonata-paint-peeling/185473/7 https://www.reddit.com/r/Hyundai/comments/zt5lsk/warranty_extension_for_1718_elantrasonata_white/

- Colonia, NJ, USA

problem #33

Dec 012022

Sonata

  • miles
This car will not start when it is cold. I have only had this car for over one year and four months. The car ran perfect up until we began to have extreme cold weather. This is so dangerous because it could be an emergency and my car will not start. I have done my research and discovered that this is an ongoing issue with Hyundai. And nothing has been done about it.

- Martinez, CA, USA

problem #32

Dec 072022

Sonata

  • miles
For the past 3 Oil changes, I find myself having to add 5 quarts of oil to my car after driving over 1,000 miles from getting my oil change. This third oil change I have added 15 quarts of oil to my car due the check oil light comes on. When I first purchased this car in March 2021, I didn-??t experience this issue. I-??ve never had to add oil to my vehicle before an scheduled oil change. Whalen the oil is checked due to the light coming on, it-??s boned dry.

- Willingboro , NJ, USA

Read the next 20 complaints »