Hyundai Sonata, Santa Fe, Tucson & Kia Optima, Sorrento, Sportage – Model Years 2011-2019 Have Defective Theta II Engines Subject to California Lemon Law

**UPDATED 03/01/2021: The opt-out period for the Hyundai/Kia Class Action Settlement regarding the manufacturers’ defective Theta II engines has ended. If you have not opted out of the class action, you are subject to the terms of the settlement reached between Hyundai/Kia and the class and can no longer opt out.**

Many model year 2010 to 2019* Hyundai and Kia vehicles are equipped with defective 4-cylinder Theta II engines that impair the use of the vehicle, its value, and your safety. Theta II engine defects can cause, among other problems, loud engine knock, stalling, delayed or no acceleration, and in many cases, can lead to fire. 

Is This Your Car or SUV?

If you purchased — new or used — or leased one of the following cars or SUVs:

  • 2011 – 2019* Hyundai Sonata
  • 2011 – 2019* Hyundai Santa Fe and Sante Fe Sport
  • 2010 – 2019* Hyundai Tucson


  • 2011 – 2019* Kia Optima
  • 2012 – 2019* Kia Sorento
  • 2011 – 2019* Kia Sportage

and have experienced any of these problems with the engine, you may have a lemon under California’s Lemon law. If you have brought your vehicle to the dealer at least two times, and the dealer has not been able to repair the problem, duplicate the problem, or you have been told there is nothing wrong with your Hyundai or Kia, you may be entitled to a buyback or repurchase under the California Lemon Law.

(*For 2019, only vehicles manufactured before the production of the Knock Sensor Detection System Technology are included in this list.)

Consistently Defective Hyundai/Kia Theta II Engines

The Hyundai Theta II Engine has, for years, been the center of continued controversy and legal battles for Korean automaker Hyundai/Kia. The Theta II Engine is the infamous second generation of Hyundai 4-cylinder engines available in 2.0, 2.4, and 2.0 Turbo variants that has gained notoriety for all the wrong reasons. 

The first Theta II engine was built at a manufacturing plant in Alabama. After time and many Theta II vehicles on the road, Hyundai noticed an increase in warranty claims related to loud engine noises and check engine lights. Many Hyundai and Kia owners have reported serious problems with their Theta II equipped vehicles including loud engine knock, seized engine, excessive oil consumption, engine stalls while driving, accumulation of oil sludge in the engine, and unfortunately in many cases spontaneous engine fires. Many owners reported the issues continued well after the warranty period had expired. 

By the summer of 2015, the National Highway Traffic Safety Administration (NHTSA) took notice and began asking questions about the reported engine-related complaints. Hyundai reported to NHTSA it did not think the problem was safety related and therefore, did not warrant a recall. 

After years of investigations and denials by the automaker, Hyundai ultimately admitted that defects in a deburring process used on the engines during manufacturing caused metal debris to be left behind around the Theta II engine’s crankshaft. The metal debris then wreaks havoc on the engine’s internal components and restricts the flow of oil throughout the engine, leading to the slew of dangerous problems reported by consumers. 

In September 2015, following investigations by the NHTSA Hyundai was forced to recall 470,000, 2011-2012 Sonatas due to the reported engine failures and thousands of spontaneous fires. A former-engineer and whistleblower within Hyundai reported the Theta II problems were known to the automaker even as it denied the existence of any defects with the engine for years.

In March 2017, Hyundai expanded the recall to include 572,000, 2013-2014 Sonata and Santa Fe Sport vehicles, and  618,000 Kia Optima, Sorrento, and Sportage vehicles equipped  with the defective Theta II engine. In May 2017, NHTSA launched a formal investigation into the Hyundai/Kia recalls to determine whether all affected vehicles had in fact been included in the recall and the extent of the manufacturers knowledge of the defect. 

Owners have reported the problems for over a decade while Hyundai only offers temporary fixes to address the symptoms of the dangerous and recurring problems with Theta II equipped vehicles. Despite all of the recalls and investigations, Theta II-equipped Hyundai and Kia Vehicles continue to have the same problems today. 

Currently, there are two class action settlements pending in the United States District Court for the Central District of California for Hyundai and Kia vehicles equipped with the problematic Theta II engine. These lawsuits, with court appointed class counsel, allege that the Class Vehicles suffer from a defect that can cause engine seizure, stalling, engine failure, and engine fire, that engine seizure or stalling can be dangerous if experienced and that some owners and lessees have been improperly denied repairs under the vehicle’s warranty.  If you have not opted out of these class action settlements, the time has passed to do so and you are subject to the terms of the class settlement.

More information regarding the pending class actions settlement can be found at: 

For more information call the experienced trial attorneys at (833) 4MY-LEMON for a free case evaluation.

DisclaimerThe information provided in this post is for informational and educational purposes only regarding aspects of the California Lemon Law.  It is intended for California Consumers only.  This post is considered an advertisement by attorney Richard M. Wirtz and Wirtz Law APC. You should not rely on any of the information provided in this advertisement and no legal advice is given by the advertisement. No attorney client relationship is established by viewing this advertisement. A written signed engagement agreement between you and Wirtz Law APC is required to create an attorney client relationship. You should immediately consult an attorney which is experienced in California Lemon Law. Attorney Richard M. Wirtz is responsible for the content of this post.  Prior results do not guarantee similar outcomes.