So engine light kept coming on had it checked out mechanic did not find anything wrong. It was my daughter's car and she was the second owner so Hyundai only offers warranty to 60K which we had no idea. Car stalls in the middle lane on interstate during rush hour traffic, she could have been killed right there. She was able to get it going finally and barely made it home. I tried to take it for oil change next day and did not make it there, car died on the way there after driving very bad and loud noises coming from the engine. Took the car to the mechanic's and they said the engine was messed up and needed to be replaced. Oil had been changed but was approx 10K past the due date - this should not kill an engine. They said they could find a used engine with 109K on it which was well past the original 66,168 miles on the Elantra for $4,000 and install for another $4,000. After seeing all the issues with Elantra's engines it was not worth it, as we felt it most likely would happen again and life is too precious to take another chance with this vehicle. Pretty pathetic experience which my daughter is stuck paying for - and Hyundai was well aware of these engine problems but couldn't care less.

Car only has 120k miles and it started knocking and turning off which left me and my family on the side of the hyw several times, but it was my only transportation. I took it to two repair shops and was quoted ridiculous prices because the engine failed and needed to be replaced. I did everything right, so I thought. This has been the worst experience in my life. My first financed car and I had to pay a car note & insurance on a car I couldn't drive for 3 months due to repair cost. I had to get a second job and fell behind on all my bills not to mention the cost for ubers and lyfts.

Hyundai should be sued for making such a faulty car. Both repair shops told me I had purchased the worst car manufactured and that they had many customers with the same model car experience engine failure under 150k miles. My car only had 120,237 and no words can describe owing a repair shop 7k to replace an engine on a car that I owe 15k on. Sad thing is that the dealership charges twice as much as third party repair shops to fix a problem that they know exist in these trash engines.

I bought a used 2018 Elantra GL with just over 31,000km on the odometer October 8th 2019. Within the next few days, I noticed that during a cold startup there is a rattling, ticking, or knocking sound coming from the engine. Someone else (Bill P.) posting a complaint for the same car except a 2017 said "It sounds like a marble in a glass gar being shaken." When I listen with the hood up and my head near the engine it is hard to tell if it is coming from the cylinder head or the block. Could be either/or, hard to say without a stethoscope (might buy one, haha).

The sound is very similar to what I know as piston slap, but I couldn't say with 100% certainty. It is the worst under load and within the first couple minutes after running if it was started from dead cold. It goes away once the engine is up to operating temperature. If the engine is still warm from a previous trip, it will not be heard at startup. I live in a cold area of Canada. On days that it is -5C or less, it is noticeably louder. But even in +10C it can be heard at startup. Not sure about really hot days since I have not owned the car through a summer yet.

After reading about all the piston slap problems in the Nu 1.8L engine in the 2011-2016 Elantras, I sure hope this isn't a continuing problem into the 2017-18 generation with the Nu 2.0L engine!

My Elantra has the 2.0L Atkinson engine and I hear rather loud rattle/almost piston slap sound for the first few minutes on cold startup. It is noticeable below 10 degrees Celsius when the car is first started up and more noticeable when you rev the engine or under acceleration. If it is below zero Celsius it is very noticeable. Once it is up to operating temp it goes away. However, it worries me and makes you wonder how long the engine is really going to last. I heard a lot of these engines by Hyundai eventually produce piston slap and need to be overhauled. Not a good problem to have.

I bought my new 2018 Elantra SEL in Dec. 2018, so I've had he car a bit less than 3 months now and racked up just over 3k miles. Within the first few days of ownership, I noticed a pinging, rattle sound from the engine at lower revs under moderate to heavy throttle. From my understanding, prolonged pinging can cause serious engine damage, so I'm very concerned...beside the noise being very unnerving.

I took the car to the dealer. The mechanic said he heard the noise, but hooked the car up to their scan tool and the computer wasn't throwing any codes, so they haven't a clue what the problem could be. He said to make sure I'm using only top tier gas, which I have been since my first refill. He then recommended I try a tank of premium. So here I am, running on premium. The pinging seems less severe, but it's still very present. Once I burn through the premium, I'll fill up with 87 again and bring the car back to the dealer. I fully expect similar outcome from the 2nd visit as the 1st. After visit #3, I'll pursue a resolution through my state's lemon law.