The engine has produced knocking sound at 134000 miles. I replaced spark plugs, ignition coil and upgraded the fuel to higher octane, but the problem is unresolved

- San Diego, CA, USA

Left a location driving my vehicle normally the check engine light comes on, then my vehicle loses acceleration and then my vehicle stalls and I almost didn-€™t make it home.

- Long Branch, NJ, USA

My daughter purchased her first car, a 2017 Hyundai Elantra, last December (2020). She drove it for the first few months without any major issues but then it started having issues with the car -€œjerking-€ and stalling every time she drove it. It actually stopped in the middle of the road multiple times and she had to start it up again, which is highly unsafe. The check engine light came on and she took it to the local O-€™Reilley auto parts for the free diagnostic scan. It pulled up a camshaft sensor. Her best friend-€™s dad is a local mechanic and has a high-tech reader, so he plugged it in and it pulled up camshaft/crankshaft. He also noted that the oil was really low (she had it for six months at this point). No oil light on. They added oil to it. The car sat in our driveway for a few months until we could afford to repair it. Took it to the local repair store and they stated that one of the major issues was the timing chain was loose due to -€œworn sprockets-€ (which the mechanic stated appeared to be a manufacturing defect as they are too short to properly grasp like they are supposed to). After completing a $1800 timing belt repair they are now stating that, that was not the only issue and that the motor itself is going to need to be replaced. At this point, the car is not valued at the price of the repairs and replacement, leaving my daughter without a car and with a finance payment. I-€™m at a loss of what to do. I do not know much about cars but I do know that a car that was manufactured in 2017 should not need an entire motor replaced by 2021.

- Florence, OR, USA

Check engine light came on while driving to dealership for an unrelated recall on door handle. A diagnosis of the car computer showed a code of P0128 Coolant Thermostat. Further check of information on this particular problem produced a Technical Service Bulletin from the manufacturer, Hyundai, Number 18-01-012. This bulletin was found on the NHTSA site. I notified the dealership and sent a copy of the bulletin. The dealership refused to comply with the bulletin and never returned our calls. I tried another dealership and Hyundai corporate office in California, and again was refused to comply with the bulletin. The replacement of this part was to be performed by any dealership if this particular vehicle was brought in for any type of service. The dealership manager, service manager and service department were all rude to my wife and myself in person and by phone. One person told my wife to fix it herself and hung up on her. Since obtained this bulletin from NHTSA website I feel that the refusal to perform the work is in direct violation of a known defect to this car. There is no recalls listed for this car even though I received a recall notice concerning the door opening flaw. There is nothing noted about the problem with the Coolant Thermostat even though the Manufacturer and NHTSA have both reported the problem. This repair was to be made regardless of whether there was a noted problem or not, as per the writing on the Technical Service Bulletin.

- White Stone, VA, USA

Elantra was running fine, parked the car at the store and went to start it and it didn't start. Tried starting it multiple times before smoke started coming out of the engine. Had the car towed to a Hyundai dealership to have it diagnosed and found out the engine was seized and the starter was blown due to trying to start the vehicle.

- Fall River, MA, USA

The contact owns a 2017 Hyundai Elantra. The contact stated that while operating the vehicle, the check engine warning light would remain illuminated. The contact stated that the vehicle would jerk and hesitate and experience unintended acceleration. The vehicle was taken to the local dealer who diagnosed that the fuel injectors were faulty. The vehicle was not yet repaired. The manufacturer was contacted regarding the failure, but no assistance was offered. The approximate failure mileage was 60,000.

- Clinton, MD, USA

According to the Hyundai Dealership, located in Corona, CA, the Hyundai Elantra's are known for the ignition coil to go out. This is also not covered under warranty and list below of why it should be: This can cause Engine misfiring in a vehicle whose ignition coils have failed. Trying to start the engine of such a vehicle will result in engine misfiring that sounds like a coughing, sputtering noise. When driving at high speeds, jerking and spitting will be seen in the behavior of the vehicle. A vehicle with a failed ignition coil will also result in vibration when it is idling at a stop sign or light. Driving with a faulty coil pack can damage other components of the engine. Also most cars will register a faulty coil and immediately stop gas feed to that cylinder. However, damage may be caused if the fault isn-€™t registered by the PCM and the dead cylinder continues to receive gas. Your catalytic converter and oxygen sensors may become contaminated by raw gas and need to be replaced. This can be dangerous if it is a known common issue in a Hyundai Elantra and cause an accident when travelling at a higher speed. I was at a stop when this problem occurred for me but was able to safely move out of the way.

- Corona, CA, USA

Abbreviated. Full description in files. Since July 2021, I have had intermittent issues with my 2017 Hyundai Elantra. When trying to accelerate, the car would struggle to move and feel like it was about to stall. The engine light would come on any time I would step on the gas. It was a danger should my car refused to accelerate while making a turn, merge, etc. On 8/31, I brought my car to Healey Hyundai. However, Healey could not fix the car, as the error codes were not in the car. On 9/6 I was able to drive to Healey Hyundai within the same day of the issue. The error code, a misfire on cylinder 2. On 9/16, Hyundai Motor Corp recognized there was a premature failure of the ignition coil on cylinder 2. A warranty repair was done to replace the ignition coil. Once fixed, a representative from Healey Hyundai acknowledge they had seen this issue before. They went so far as to warn me that the other ignition coils could go at any time. On 9/27 at 11 am, the issue occurred again and worse than I ever experienced it. The engine light turned on and my car struggled to move. For 15 minutes until I was able to safely stop. Once off, the light went away, and it appeared to operate normally. On 9/28 at 1 pm, I brought the car to Healey Hyundai again. It was 26 hours, 30 miles, and 4 starts since the issue occurred. However, the error codes were again missing from the car. Healey Hyundai was not able to reproduce. And while I have felt the car shutter and hesitate since, it is not enough for the engine light to turn on. The original ignition coils installed in the car are faulty. They overheat during normal use causing them to melt and warp. It also explains why the issue has decreased as the weather cools. Also alarming is the excessively short period of time error codes are stored in the computer. It is a matter of time till my car fails again and I am afraid for my safety when it does.

- Poughkeepsie, NY, USA

While accelerating on moderate incline engine has failed three times and souns like it-€™s flooding. After taking the vehicle to the dealership, they reported no engine failures or misfires were documented by the vehicles OBD. Engine has become excessively noisy, but after a 17 mile driving test by the dealership, they reported not experiencing any issues or hearing any noises. Vehicle Mileage: ~48.5K miles.

- Scott Afb, IL, USA

The contact owns a 2017 Hyundai Elantra. The contact stated while driving at 25-30MPH, the vehicle inadvertently stalled. The contact stated he saw smoke coming from underneath the hood of the vehicle. The check engine warning light illuminated. The contact veered to the side of the road, where he checked the engine and oil level but could not determine the cause of the failure. The contact stated he continued to drive the vehicle, however, the vehicle would not go past 30 MPH. The independent mechanic came to the contact's residence and diagnosed that the engine had failed. The vehicle was towed to the dealer who diagnosed that the failure was caused by a lack of engine oil. The manufacturer was notified of the failure and advised that they would cover the replacement of the engine based on the dealer's diagnosis. The vehicle was not repaired. The approximate failure mileage was 101,000.

- Miami, FL, USA

The engine shakes while driving slowly or idle and starts to act like it will stall. Happened in the middle of driving several times including on the freeway where I was lucky enough to get off to the side of the road without getting hit. Turns out the ignition coils are bad and was confirmed after trying to replicate the problem several times. This has been reported several times for this make and year. Looks like some years were previously recalled but not my specific vehicle. Yet it was still a problem. This presents an extreme safety hazard as you do not know when it will stall and can do so while driving. With repeated reports of this part being affected, there should be a recall. Seems like hyundai is trying to save money at the expensive of the driver's safety. My previous Elantra lasted for 13 years without this problem.

- Sacramento, CA, USA

Heavy engine knocking, no warning lights came on, had low oil (oil changed 1.5 months ago), car stalled 30 seconds after pulling to expressway shoulder

- Audubon, PA, USA

Engine stall while turning. Metal flakes in the engine. Engine completely failed requiring a new engine. Factory paint failed and bubbles off.

- Annapolis, MD, USA

Randomly stall all different times all lights will light up and coast until stopped. Down a hill and to turn it would stall. Go into 8 most serious accidents. I need someone to reach out cuz this car is not safe to drive wit kids at all

- Providence, RI, USA

The contact owns a 2017 Hyundai Elantra. The contact stated that after starting the vehicle, the vehicle was idling rough. The contact stated that the check engine warning light was illuminated. The vehicle was taken to a local mechanic where it was diagnosed with needing the camshaft and crankshaft replaced. The vehicle was repaired but continued to experience failure. The manufacturer was informed of the failure and informed the contact that they were unable to assist. The failure mileage was approximately 80,000.

- Richmond, CA, USA

The car is losing antifreeze. There is no antifreeze on the ground. From my understanding this has been an ongoing problem with this model of car and it needs to be a recall. I was informed that it-€™s losing antifreeze due to deficits in the exhaust system.

- Providence Forge , VA, USA

Consumes oil at a fast rate about 1.5 quarts every 1,000 miles. Car burns oil way too fast the dealership and Hyundai do not want to deal with it.

- Long Branch, NJ, USA

The contact owns a 2017 Hyundai Elantra. The contact stated that while her son was driving approximately 35 mph, the engine seized. The driver detected smoke and oil leaking from the vehicle. The vehicle was pushed into a parking lot. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was notified however, no further assistance was provided. The contact mentioned the rod punctured the engine.The approximate failure mileage was 72,000.

- Runnemede, NJ, USA

Drove my car yesterday when it stalled. I was able to start it again and pulled to the side of the highway. The engine was knocking loudly. I turned off the car and called a tow truck. When hyundai received my car they told me it was the rod bearings.they initially told me id be covered regardless of warranty as its a known issue. They called me late that day and told me they won't cover it since I'm 18,000 over the powertrain warrenty. This very problem has been recalled from 2013 upto 2019. However my car isn't listed. They told me ill need a new engine which costs $6000 for parts and labor. After researching im not the first this has happened to.

- Mission, AL, USA

I noticed the car losing power (2017 Elantra) took it to my local mechanic and got a misfire code on coil 3. Replaced it and the next day took a long trip to New Jersey, the car stalled at low speed with the CEL on pulled to the side restarted the car and proceeded to drive the rest of the way. I felt unsafe as the engine felt like it was struggling. On the way back I decided to tow it back to NY. I drove it the next day to my mechanic and he said there were no stored codes, he drove it and said he could do nothing. I drove it the next day and the same problem happened, luckily on a side street. Took it back to him and made him drive it around for a 4 day period nothing happened. My son drove it and the same issue happened luckily on a side street. I then took it to the Hyundai dealer and they said they got a misfire code. They replaced the remaining coils, changed the engine coolant and cleaned the fuel injection system. Maybe me wait practically 2 weeks with no loaner. Drove the car and the same issue occurred. Again luckily on a side street. I called my mechanic and he said drive locally and if it happens to call him so he will hook up a scanner to get a code. Right in my neighborhood the same thing happened so I called him and he was unable to get a code, he thought it could be either cam or crankshaft sensor, he tried both and the stall occurred when he was driving, he then changed the MAP sensor and drove it for 30 minutes without an issue. I went away for 5 days and came back and drove the car which seemed fine, but the same problem happened. This is a dangerous problem and feel unsafe driving this car. It has only 46.000 miles on it. I have a case opened with corporate and waiting for them to contact me.

- Syosset, NY, USA