Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2008 Hyundai Sonata owners, lightly cleaned up (personal details are redacted by NHTSA).
Bought in 2023 @ 98k miles. Have had trouble with 1.it would only start in drive, then that seems to have self corrected. 2. In drive, car would not accelerate properly, and would slow as though I was braking, but no foot on brake. Had rear brake sensor replaced, seemed better for a while. 3. Developed oil leak at 120 miles which valvoline characterized as "not serious...just keep checking it and topping it off." So, have been doing that. Today after oil change, it began running rough, lots of vibration, then the shifting problem, sluggishness, and new..smoke from under hood on driver's side. No check engine lights at all. Nothing registered as hot or overheating. Turned off car, checked oil and trans fluid, both in proper range for warm engine. Let car sit and cool for an hour. …
Tl* the contact owned a 2008 Hyundai Sonata. The contact stated that the check engine indicator illuminated. The following day, the vehicle started making a knocking and rattling noise, similar to metal on metal, while driving 40 MPH. The contact pulled the vehicle over to the side of the road and noticed flames under the hood near the engine. The fire was extinguished by the fire department. There were no injuries and a police report was not filed. The vehicle was totaled and towed to a junk yard. The dealer and manufacturer were not contacted. The vehicle was not diagnosed. The failure mileage was 125,500.
On the 3.3l engine there is a fault in the intake manifold gasket that causes oil to leak onto the alternator causing premature alternator failure. If the vehicle loses power while driving this can increase the risk of a crash. This problem has happened on other vehicles with this same engine such as the veracruz and a recall has been initiated. For some reason the recall does not extend to the Sonata as it should. The following is from the veracruz recall involving the same engine. "Hyundai motor company (Hyundai) is recalling certain model year 2007-2012 veracruz vehicles manufactured from December 26, 2006, through July 24, 2012. The affected vehicles May experience an oil leak from the front cylinder bank valve cover gasket. …
This issue effects 2.4 liter gasoline direct injection engine model sonatas. Metallic debris May not have been fully removed during manufacturing of the engine crankshaft. If the debris was not completely removed, oil flow May be restricted through the connecting rod bearings, causing connecting rod damage. A worn connecting rod bearing will produce a metallic, cyclic knocking noise from the engine and possible engine failure resulting in the need to rebuild or replace engine. My engine first failed out in October of 2016 and caused me to require an engine replacement. In August 2017 that same engine had the exact same issue happen to it. This has been 2 of the 2.4 cyl I-4 engines having the exact same issue on the exact same care with around the same mileage on both engines. There have been many various complaints reported all over the internet effecting this engine. …
Upon starting the car, I heard a high-pitched whine from the engine that increased in volume and intensity as I accelerated (in town), and then I observed two puffs of smoke or steam arise from under the front of the hood. I immediately stopped at a nearby mechanic, who observed that the front cylinder bank valve cover was leaking oil. The whine, which gradually went away, May have been oil getting onto the alternator belt. Fortunately, we seem to have caught this in time, as the alternator did not appear to be damaged, but it easily could have been, as the edge of the valve cover hangs directly over the alternator in the 3.3l v6 engine. The leak May have been more of a "sweat" for an undetermined amount of time; only the whine alerted me to anything being wrong, and May have been a sign the leak was getting worse over time. The mechanic replaced the valve cover gasket. …
On July 19, 2016 at or about 1500 hours, I was driving to the store to get some food, on the way out my apartment complex, I believe my Hyundai Sonata 2008 allowed me to go about two blocks down from where I live to shut off in the street right before I approached the stop sign. I also remember hearing two weeks prior to my vehicle shut off, while driving I heard this knocking sound in my engine, I thought it was the new starter that was replaced but then a day or two later it stop making that knocking noise. I called around to find answers no one had a clue to what was going on with this vehicle. Everything was working just fine until July 16, 2016. I had this vehicle since April 17, 2009 and I can't not believe this vehicle has a major issue like this at point and time. …
While driving 65 MPH on interstate, a began to hear a knocking sound that became louder and louder. I had two mechanics look at my car and both said that the car was about to throw a rod. On December 13, 2014 the car stop running altogether. I had no warnings prior to this happening, and I had regular oil changes. In fact I had the oil changed just two weeks prior to this incident. I am having ricart Hyundai in columbus, ohio (where I purchased the vehicle brand new) look at my car on April 2, 2015. I am interested in what they are going to say or do about this since it is no longer under warranty. I just want them to tell me exactly what happened to this engine and what if anything they (manufacturer) can do about repair. This is my second Sonata (I still have the other car with over 150,000+ miles) and never had any problems like this before. …
While driving the seat belt light came on. About a minute later the radio shut off. Next most of the dash lights came on , the engine would not make power/accelerate, and the braking seemed weak/jerky. Pulled into a parking lot as soon as I could. Now all dash lights were on/blinking and the radio, sunroof, windows etc would not work. Thinking it was an electrical issue I left it running to investigate. Next thing I know the car is overheating even though the gauge isn't showing it. Steam everywhere and the overflow popped the cap off. Shut the car off. Once the car cooled I was able to see what happened. Oil has been dripping on to the alternator from a leak in the valve cover gasket. This killed the alternator which in turn caused the control/braking/acceleration issues one it was on battery only. I'm assuming the fan was not cooling either which resulted in the overheating.
While driving the check engine light and ESC light go on simultaneously. When this occurs, the car goes into reduced power mode ("limp mode") and you are not able to drive above 15 or 20 MPH. This is a very dangerous situation, especially when driving on the highway. This is a known issue with Hyundai in which they issued TSB #'s 09-fl-003-2 and 10-fl-010. The TSB's address a faulty throttle position sensor which is to be replaced with a new one with different settings than the original. One the part is changed, an update to the electronic control module is required. There are numerous accounts of this incident happening. How can a flaw of this magnitude not warrant a recall?
When vehicle is started from a cold start, there is a noticeable rattle coming from engine that lasts about 3-7 seconds. Also while accelerating, the rattle is persistent with throttle input. I was told that the problem is the timing chain tensioner and that the Hyundai sonatas have defective timing chain tensioners. I went to the Hyundai dealership and they quoted me $1,100 to fix the problem and made me aware that there was a TSB but not a recall on the part even though there is a revised tensioner. This is a ongoing issue and a hazard because the chain could have to much slack and cause the the timing to be off and future damage for the engine.
NHTSA investigations
Loss of Motive Power
The National Highway Traffic Safety Administration (NHTSA) received a letter dated July 13, 2022, petitioning the Agency to initiate a safety defect investigation into loss of motive power allegations attributed to oil drain pan assembly failures on certain Hyundai Motor America, Inc. and Kia America, Inc. vehicles spanning Model Years (MY) 2005-2021.
Engine complaints in other Sonata years
Frequently asked questions
How common are engine problems on the 2008 Hyundai Sonata?
NHTSA has 49 complaints about the engine & cooling of the 2008 Hyundai Sonata, 12% of the model year's 425 complaints.
Is there a recall for 2008 Hyundai Sonata engine problems?
No. NHTSA lists no engine & cooling recall for the 2008 Hyundai Sonata, though it has 3 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 2008 Hyundai Sonata engine problems start?
Half of the complaints with a recorded mileage happened before about 113,000 miles, and 6% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 5 fires and 1 injury to engine & cooling 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.