Car consumes excessive oil -?" one quart about every 500-700 miles. This has caused sludge in the engine and the car hesitates significantly on starting from a stopped position and now hesitates even at highway speeds. This has become a definite safety issue. If the car stalls it is only a matter of time before I am hit by another driver. The dealer first stated the oil consumption was fine IF it was one quart every 1,000 miles and that no repairs would be needed. My car is consuming almost double that amount of oil. Dealership agreed to look at it; stated the car needs a new engine. Hyundai refused to even do an oil consumption test, let alone repair/replace the engine. The -??sludge-?? in the oil that Hyundai states was present is a result of the oil consumption (even the dealer service department verbally agreed). I-??m literally putting new oil in it about once a week! There is no possibility this would NOT cause sludge. In addition, dealership said to expect the engine to fail fairly soon. Hyundai claims the car was not maintained properly; however, that is untrue. I-??ve submitted records to them that I had. The warranty has no requirement that the oil must be changed or maintained by a certain individual or company. Without a new engine, the car will continue to hesitate and will eventually fail. Hesitation (and especially engine failure) subjects me to a much higher possibility of a crash causing injury or death to myself or someone else. Hyunadai should absolutely recall the thousands of vehicles having this exact same issue.

- West Lafayette, IN, USA

I was traveling on a highway when a "hybrid system warning" suddenly appeared on the dashboard. Every dashboard warning light illuminated. The car began to lose power. I exited the highway immediately and the car began to have sporadic power and was "lurching." I immediately pulled onto the shoulder and at that time another warning on the dash appeared within a minute or two of the first warning that said "shut engine off." The computer screen began to flash on and of and the windows would not roll up smoothly. When the tow truck arrived the car wouldn't start and it didn't recognize the key fob. Hyundai now has the vehicle and claims the car needed a "software update", but they cannot tell me if it will ever happen again and cannot tell me why the car goes into critical failure when it needs a mere software update. This is the second time this has happened. The first time it was repaired under a voluntary recall campaign about a year ago. This is an extremely dangerous occurrence as the car loses power without warning. I was fortunate to be near an exit when it happened and able to safely get off the highway, but that was just luck. The manual indicates that a hybrid system warning means that the car can potentially go on fire.

- Larchmont, NY, USA

The transmission in my vehicle makes a whine when shifting at about 35-40 miles per hour. No other car I ever drove made that noise. Hyundai has replaced the transmission 3 times and they still could not fix it. After the third replacement they said it's normal and that other Sonatas make that noise. That cannot be true. They did not replace the transmission 3 times if that noise is normal. If it IS true and other Sonatas make that noise, there may be a defect that will turn dangerous in other Sonatas. The second time the transmission was replaced, the service manager told me they found metal fragments in the transmission fluid. I don't know what problem this defect will cause later on. If you would like to inspect my car to determine if this is dangerous, I can make it available. Thanks! P.S. - Below, I have to pick a date of the incident and mileage at that time (so I chose when I first reported it to Hyundai), but this happens every time I drive the car.

- Milford, CT, USA