The federal government’s investigation into Kia’s engine safety remains a focal point for thousands of drivers across the country. The National Highway Traffic Safety Administration (NHTSA) has moved beyond a simple recall notification, initiating a formal audit query into the effectiveness of the remedy provided for over 137,000 vehicles. This audit, specifically targeting 2021-2023 Kia Seltos and Kia Soul models, addresses a critical question: is the "fix" actually preventing engine failures, or is it merely delaying the inevitable?

The Mechanics of the Piston Oil Ring Defect

To understand why the NHTSA audit is so significant, one must first look at the mechanical failure at the heart of the issue. The affected vehicles are equipped with 2.0-liter Nu MPI engines. These engines rely on piston oil rings to seal the combustion chamber and regulate the flow of lubricant. In early 2025, it was confirmed that a supplier-level manufacturing defect led to inconsistent heat treatment of these rings, resulting in excessive hardness.

When a piston oil ring is too hard, it becomes brittle and abrasive. Instead of gliding smoothly against the cylinder wall, it begins to score and scratch the surface. This physical damage, known as cylinder bore scuffing, leads to a cascade of engine problems. First, engine oil begins to seep past the compromised rings into the combustion chamber, where it is burned off during the ignition cycle. This results in rapid oil consumption that many owners might not notice until the low oil pressure light flickers—often too late to prevent permanent damage.

As the scoring worsens, the engine loses compression. Drivers may experience a noticeable drop in power, rhythmic knocking sounds (often compared to a marble in a tin can), and eventually, a total loss of motive power. In the most severe cases, the friction-induced heat or the ejection of oil onto hot exhaust components can trigger an engine compartment fire.

The Original Recall (25V099) and Its Limitations

In February 2025, Kia America filed safety recall 25V099 to address these risks. The population included 137,256 vehicles. The proposed remedy at the time was two-pronged: a dealer inspection to identify engines already suffering from damage and the installation of the Piston Ring Noise Sensing System (PNSS) software.

According to the recall filing, if the dealer inspection revealed specific trouble codes or physical scoring, the engine long block would be replaced at no cost to the consumer. However, for vehicles that "passed" the initial inspection, the software update was the primary safeguard. The PNSS was designed to monitor engine vibrations and alert the driver if frequencies associated with piston ring failure were detected. If the software triggered a warning, the vehicle would enter a "limp home" mode, limiting speed and RPM to prevent catastrophic failure while the driver sought service.

Why the NHTSA Opened Audit Query AQ 25001

The transition from a voluntary recall to a federal audit query (AQ 25001) in August 2025 signaled a breakdown in the remedy process. Between April and June 2025, the NHTSA’s Office of Defects Investigation (ODI) received dozens of complaints from owners who had already received the recall "fix." These complaints highlighted three systemic failures:

  1. Ineffective Remedy: Owners reported that their engines failed shortly after passing the dealer inspection and receiving the software update. This suggests that the visual inspections and vibration tests used by dealerships may not be sensitive enough to detect early-stage cylinder scoring.
  2. Unavailability of Parts: Many drivers were told that despite their car showing symptoms of failure, replacement engines were backordered for months, leaving them without reliable transportation or forcing them to drive a potentially hazardous vehicle.
  3. Inconsistent Inspection Standards: There appears to be a significant disparity in how different dealerships interpret "acceptable" levels of oil consumption or engine noise. Some owners reported being turned away even when their cars were consuming a quart of oil every 500 miles, with dealers claiming this fell within "normal operating parameters."

The PNSS Software Debate: Safety Tool or Band-Aid?

A central focus of the ongoing NHTSA audit is the Piston Ring Noise Sensing System. While Kia maintains that the software is a valid safety measure to prevent fires and sudden stalls, some automotive experts and consumer advocates argue that it is a "reactive" rather than "proactive" solution.

The software does not fix the physical defect of the hardened rings; it only alerts the driver once the damage is advanced enough to create a specific acoustic profile. For an owner of a 2022 Kia Seltos, this means the software might only intervene once the engine is already significantly damaged. Furthermore, if the software fails to detect a specific type of failure, or if the driver is in a high-speed highway environment when "limp home" mode activates, the risk of a rear-end collision increases.

Identifying Symptoms in Your Seltos or Soul

If you own a 2021-2023 Seltos or Soul, relying solely on the recall software may not be sufficient for peace of mind. Proactive monitoring is essential. The following symptoms are indicative of the piston ring issue even if the dashboard warning lights remain off:

  • Abnormal Oil Consumption: Check your oil level every 500 miles. If you notice a drop on the dipstick that requires adding a quart or more between scheduled changes, the engine is likely burning oil due to ring failure.
  • Rattling or Ticking: Pay close attention to the engine sound during cold starts and acceleration. A metallic "pinging" or "knocking" that increases with engine speed is a classic sign of internal damage.
  • Exhaust Smoke: While modern catalytic converters can mask some oil burning, a bluish tint to the exhaust smoke, especially under heavy acceleration, suggests oil is entering the combustion chamber.
  • Reduced Fuel Economy: As the engine loses compression due to cylinder wall damage, it has to work harder to maintain speed, leading to a noticeable decrease in MPG.

Navigating the Dealer Inspection Process

The NHTSA audit has highlighted that the dealer experience is where many owners encounter roadblocks. When taking your vehicle in for the 25V099 recall or a follow-up related to the audit, documentation is your most valuable asset.

Do not simply tell the service advisor that the car "feels weird." Instead, provide a log of oil consumption. If you have to add oil, take a photo of the dipstick before and after, and keep the receipts for the oil you purchased. If the engine is making a noise, record a video on your phone and show it to the technician.

If a dealership refuses to perform an engine replacement despite evidence of oil consumption and noise, you have the right to request a secondary review from Kia America’s corporate customer service. Furthermore, filing a report directly with NHTSA.gov is crucial. These individual reports are the data points that fuel the audit query and can force a manufacturer to expand its recall efforts or offer better compensation.

The Regulatory Path Forward: What the Audit Could Change

What is the expected outcome of the NHTSA audit? Historically, audit queries serve as a high-pressure tool to ensure manufacturer compliance. The audit into the Kia Seltos and Soul recall could lead to several scenarios:

  • Revised Inspection Protocols: The NHTSA may mandate that Kia use more rigorous testing methods, such as borescope inspections (using a camera to look inside the cylinder) rather than just software or vibration tests.
  • Expanded Engine Replacement: If the audit proves that the software is insufficient, Kia may be forced to replace engines in a larger percentage of the 137,000 vehicles, regardless of whether they have currently failed.
  • Extended Warranties: It is common for such investigations to result in a lifetime or 15-year/150,000-mile warranty extension for the engine long block, providing long-term protection for second and third owners.

Safety Considerations and Fire Risks

It is important to address the fire risk without hyperbole. While only a small percentage of affected vehicles have experienced thermal events, the risk is real. When oil leaks onto the manifold or when internal components (like a connecting rod) break and punch a hole through the engine block, fluids can ignite instantly.

If you see smoke coming from under the hood or smell burning oil while driving, pull over immediately to a safe location, turn off the engine, and exit the vehicle. Do not attempt to open the hood if you suspect a fire, as the sudden influx of oxygen can cause the flames to flare up.

Impact on Resale Value and Ownership

For many, the Kia Seltos and Soul are attractive because of their value proposition—stylish, tech-heavy, and affordable. However, a persistent engine recall under federal audit can negatively affect resale values. Prospective buyers who run a VIN check will see the open recall or the history of engine work.

For current owners, the best way to preserve value is to ensure that all recall work is documented in the vehicle’s service history. If an engine replacement is performed, ensure you have the paperwork showing the new block’s serial number and the date of installation. A vehicle with a brand-new, updated engine block may actually be more desirable than one with the original, potentially defective engine.

The Broader Context of Kia Engine Reliability

This audit does not exist in a vacuum. It follows a decade of scrutiny regarding Kia and Hyundai’s "Theta II" and "Nu" engine families. Previous recalls for bearing failures and oil leaks have cost the parent company billions in settlements and repairs. This history is likely why the NHTSA is being particularly aggressive with the Seltos and Soul audit. The agency is looking for patterns of behavior that suggest a recurring struggle with engine manufacturing quality control.

For the consumer, this means that the federal government is watching closely. The audit query is an acknowledgment that the initial recall might have been insufficient. It represents a shift toward holding automakers accountable for the long-term effectiveness of their repairs, not just the initial announcement of a fix.

Final Recommendations for Impacted Owners

As of early 2026, the NHTSA audit into the Kia Seltos and Soul recall is a dynamic situation. Owners should stay informed by checking the NHTSA recall lookup tool at least once a month. Information can change rapidly, and new service bulletins are often issued while an audit is active.

If your vehicle has already been "repaired" but continues to exhibit signs of oil loss or engine noise, do not assume that the issue is resolved. The audit exists precisely because the initial repair may have failed. Persistence at the dealership level, combined with diligent documentation and reporting to federal regulators, is the most effective way to protect both your safety and your investment.

While the 2021-2023 Seltos and Soul remain popular choices in the compact SUV segment, the shadow of the 2.0L engine defect requires a heightened level of vigilance. Maintenance is no longer just about longevity; in the case of the piston oil ring defect, it is a critical safety practice.