Kia K5 and Hyundai Sonata Expanding Gas Tank: Can You File a Lawsuit?

Written By: Jessica Anvar Stotz
Legally Reviewed By: Jessica Anvar Stotz

Owners of 2021-2024 Kia K5 and Hyundai Sonata models have reported a troubling defect: fuel tanks that swell or expand, potentially leading to performance issues and safety concerns.

A new class action lawsuit alleges that Hyundai and Kia knowingly sold vehicles with defective fuel systems, which could contribute to engine problems and other mechanical failures.

The 2025 Kia Hyundai Expanding Gas Tank Lawsuit, filed on January 9 in a California federal court, names Hyundai Motor Co., Hyundai Motor America Inc., Kia Motors Corp., and Kia Motors America Inc. as defendants.

Plaintiffs Timothy Masters and Michelle Frank-Crowder claim the automakers violated state and federal consumer protection laws by failing to disclose the defect. Attorneys from ClassAction.org previously investigated complaints before initiating legal action.

The problem appears to originate from a faulty fuel tank valve, which can cause the tank to deform under pressure. Drivers have reported alarming symptoms, including:

• Back seats popping up due to fuel tank expansion
• Loud banging noises from the rear of the vehicle
• Rough driving performance and potential fuel system issues

If you own or lease a 2021-2024 Kia K5 or Hyundai Sonata and have experienced fuel tank expansion issues, you may be eligible to participate in the class action lawsuit. Legal action could help.

What Causes the Kia and Hyundai Fuel Tank Issue?

The fuel tank expansion issue affecting Kia K5 and Hyundai Sonata vehicles appears to stem from a defect in the Positive Crankcase Ventilation (PCV) valve.

This valve is responsible for regulating the flow of pressurized air into the fuel tank, but when it malfunctions, it can allow excess air to enter, causing the tank to swell or distort under pressure.

Plaintiffs in the class action lawsuit argue that the fuel system design is flawed, particularly in how it manages evaporative emissions and air flow.

The lawsuit claims that defects in the Engine Control Module and emissions control system prevent fuel vapors and air from being properly routed to the intake manifold. Instead, these vapors accumulate in the fuel tank and other areas, leading to a range of issues, including:

• Poor engine performance and frequent misfires
• Rough idling and sudden loss of power
• Difficulty removing the fuel cap
• Strong fuel odors inside the cabin
• Problems refueling, including slow or incomplete fills
• Expansion or deformation of the fuel tank
• Increased emissions that may violate environmental standards

The National Highway Traffic Safety Administration (NHTSA) is currently investigating reports of this issue. If the agency determines that it poses a widespread safety risk, a formal recall could be issued.

In the meantime, Kia has launched a voluntary service campaign—beginning in April or May 2024—for certain 2021-2024 Kia K5 models equipped with the Gamma II 1.6L T-GDI engine.

With both legal action and federal investigations underway, Kia and Hyundai owners are encouraged to monitor developments and seek potential remedies if they experience these fuel system issues.

Which Vehicles Experience Gas Tank Swelling?

The class action lawsuit seeks to represent all U.S. owners and lessees of Hyundai and Kia vehicles equipped with the 1.6L T-GDI Gamma II engine, including:

• 2020-2024 Hyundai Sonata
• 2021-2024 Kia K5

According to the lawsuit, fuel tank distortion in these vehicles can be severe enough to cause loud popping noises and even damage other components.

In some cases, the expanding fuel tank has reportedly dislodged the backseat or bent the vehicle’s frame.

Is there a Kia K5 Gas Tank Recall?

As of now, there is no official recall for the Kia K5 gas tank issue. However, Kia has issued a Technical Service Bulletin (TSB) and launched a voluntary service campaign in April 2024 for certain 2021-2024 Kia K5 models equipped with the Gamma II 1.6L T-GDI engine.

The issue stems from a defect in the Purge Control Solenoid Valve (PCSV) check valve, which can allow excessive pressurized air to enter the fuel tank, leading to swelling, deformation, and potential drivability concerns. Symptoms reported by owners include:

• Illuminated Check Engine Light
• Rough engine performance
• Difficulty refueling
• Unusual popping noises from the fuel tank

Under Kia’s service campaign, dealers will inspect the fuel evaporative system and, if necessary, replace the fuel tank and/or the PCSV check valve. Additionally, the Engine Control Unit (ECU) software may be updated as part of the fix.

While this campaign helps address the issue, it is not an official recall. The National Highway Traffic Safety Administration (NHTSA) is currently investigating the problem. If their findings confirm a significant safety risk, Kia may be required to issue a formal recall.

For now, if you’re experiencing fuel tank swelling or related symptoms, we strongly recommend scheduling a service appointment with Kia as soon as possible.

If you own a 2021-2024 Kia K5, you should contact your local Kia dealership to check if your vehicle qualifies for this service campaign. The inspection and any necessary repairs are provided at no cost under the vehicle’s warranty.

What’s the Solution for the Kia K5 Fuel Tank Problem?

While a permanent fix may not yet be available, Kia has introduced a voluntary service campaign to address the fuel tank swelling issue in 2021-2024 Kia K5 models equipped with the Gamma II 1.6L T-GDI engine.

As part of this campaign, Kia dealerships will:

• Inspect the fuel evaporative system for signs of tank deformation
• Update the Engine Control Unit (ECU) software to help regulate fuel system pressure
• Replace the fuel tank and/or Purge Control Solenoid Valve (PCSV) check valve if necessary

If you own an affected 2021-2024 Kia K5, schedule an appointment with your local Kia dealership for an inspection. Any repairs or replacements will be provided at no cost under the service campaign.

Is there a Hyundai Sonata Gas Tank Recall?

As of now, there is no official recall for the Hyundai Sonata gas tank issue. Unlike Kia, Hyundai has not issued a Technical Service Bulletin (TSB) or launched a service campaign to address the problem.

This means there are currently no manufacturer-backed guidelines for dealerships to inspect or repair fuel tank swelling in Hyundai Sonata vehicles.

The National Highway Traffic Safety Administration (NHTSA) is currently investigating reports of this issue, however.

If the investigation determines that the defect poses a safety risk, Hyundai may be required to issue a formal recall.

If you are experiencing fuel tank problems with your Hyundai Sonata, consider reporting the issue to NHTSA and contacting your local dealership to discuss potential repair options.

Legal Options for Affected Kia K5 and Hyundai Sonata Owners

If you’re experiencing fuel tank problems with your Kia K5 or Hyundai Sonata, several legal options may be available to seek compensation or a resolution:

• Class Action Lawsuit: A class action lawsuit on behalf of Kia K5 and Hyundai Sonata owners affected by fuel tank issues has been filed. A successful class action could help recover costs related to repairs, vehicle damage, and diminished vehicle value. It might also prompt a recall of the affected models.
• Individual Lemon Law Lawsuit: If your vehicle has undergone multiple repairs for the same fuel tank issue, you may qualify for relief under your state’s Lemon Law. These laws protect consumers who purchase or lease vehicles with persistent defects that affect safety, value, or usability. Eligible owners may be entitled to compensation, a replacement vehicle, or a refund. Consulting with a Lemon Law attorney can help you determine if your case qualifies.
• Reporting to Regulatory Authorities: You can report the fuel tank problem to regulatory bodies such as the National Highway Traffic Safety Administration (NHTSA). Owners can file direct complaints with the NHTSA. Increased reports can lead to a formal investigation and possibly a recall. Complaints can be submitted directly on the NHTSA website.
• Contacting the Manufacturer: Reaching out to the manufacturer may result in resolution. In some cases, Kia or Hyundai might offer free repairs or compensation, especially if the issue gains widespread attention.

If your Kia K5 or Hyundai Sonata has recurring fuel tank problems, you may be eligible for legal recourse under your state’s lemon law.

This law is designed to protect consumers who purchase or lease new vehicles that fail to meet quality and performance standards.

If your vehicle has needed multiple repairs for the same fuel tank issue, you might qualify for compensation or a refund under this law.

Consulting with a lemon law attorney can help you assess your case and determine the best course of action to seek relief for the ongoing issues with your vehicle.

*Please note, the figures presented in the chart are approximations based on results from previous cases and should not be interpreted as a prediction or guarantee. Each case is unique and requires personalized legal guidance.

If you are considering pursuing legal options for issues with your Kia K5 or Hyundai Sonata, be sure to compile all relevant documentation.

This includes repair invoices, communication with the manufacturer, and any other evidence related to the problem.

Work with the Lemon Law Experts on Your Journey to Justice!

If you’ve been dealing with unresolved fuel tank issues in your Kia K5 or Hyundai Sonata and attempts to resolve them through your dealership or the manufacturer haven’t worked, legal action might be your next best option.

The 2025 lawsuit accuses both Kia and Hyundai of breach of warranty, fraud, unjust enrichment, and violations of consumer protection laws in California and Illinois.

While Hyundai has recently recalled over 145,000 electric vehicles due to charging issues, no recall has been issued yet for the fuel tank problems affecting the Kia K5 or Hyundai Sonata.

If your vehicle is still facing these issues and there’s no resolution in sight, seeking legal help could be your next step.

An experienced lemon law attorney can assist you in pursuing a refund, replacement vehicle or cash compensation as a result of the problems experienced with the lemon vehicle.

The Lemon Law Experts have been helping clients successfully resolve automotive issues since 2009.

We have a strong track record of handling lemon law cases for manufacturers like Kia and Hyundai, and we know how to fight for your rights effectively and get you the compensation you’re entitled to.

If you own a Kia K5 or Hyundai Sonata with ongoing fuel tank issues, contact our team to learn more today.bout how we can help you address the problems with your Kia K5 or Hyundai Sonata today.