M V8 Engine Lawsuits: Catastrophic Failures Spark Massive Class Action as Thousands of Owners Report Breakdowns

If you own a Chevrolet Silverado, GMC Sierra, or Cadillac Escalade built between 2019 and 2024, your engine might be a ticking time bomb. General Motors is facing mounting legal pressure from two major lawsuits alleging that hundreds of thousands of its V8 engines contain fatal manufacturing defects—defects the automaker allegedly knew about but failed to disclose.

With over 28,000 consumer complaints filed with federal safety regulators, reports of engines failing at highway speeds, and at least 12 crashes resulting in injuries, the stakes couldn't be higher. GM issued a recall covering nearly 600,000 vehicles in 2025, but critics say the fix doesn't address the root problem. Meanwhile, consolidated class action lawsuits are demanding billions in compensation, full engine replacements, and vehicle buybacks.

Who Is Suing General Motors?

Two parallel class action lawsuits are targeting GM's V8 engines, each representing potentially hundreds of thousands of American consumers.

The first lawsuit, Powell v. General Motors LLC, was filed in the United States District Court for the Eastern District of Michigan in February 2025. Lead plaintiff James Powell II represents owners of vehicles equipped with GM's 6.2-liter L87 V8 engine. By December 2025, eleven separate lawsuits had been consolidated into this single case, creating a legal juggernaut led by prominent law firms including Hagens Berman Sobol Shapiro, DiCello Levitt, Lieff Cabraser Heimann & Bernstein, and The Miller Law Firm.

The second lawsuit, Harrison et al. v. General Motors LLC, has been proceeding since 2021 in the same Michigan federal court. This case focuses on a related but distinct defect affecting GM's Active Fuel Management and Dynamic Fuel Management systems across multiple V8 engines. With 17 named plaintiffs and representation from Capstone Law APC, this case has survived GM's attempts at dismissal and is moving toward class certification in 2026.

Both lawsuits represent everyday Americans who invested tens of thousands of dollars in premium GM trucks and SUVs, only to experience sudden engine failures that left them stranded on highways, facing repair bills exceeding $10,000, and in some cases, risking their safety and the safety of their families.

What Went Wrong: The Defects Explained

The L87 6.2L V8 Catastrophic Failure Problem

GM's flagship 6.2-liter L87 V8 engine, marketed as a powerful, fuel-efficient powerplant delivering 420 horsepower, has become the centerpiece of a growing safety and reliability crisis.

According to the lawsuits, manufacturing defects in critical engine components are causing sudden, catastrophic failures. Specifically, plaintiffs allege that crankshafts were manufactured with out-of-specification dimensions and poor surface finishes. Connecting rods contain debris in their oil passages due to contamination during manufacturing. Engine bearings experience premature wear due to these manufacturing inconsistencies.

When these components fail, the results are dramatic and dangerous. Metal shavings circulate through the engine oil, accelerating damage to other parts. Oil starvation occurs as debris clogs passages, and damaged bearings can no longer maintain proper lubrication. The engine suddenly seizes, connecting rods break through the engine block, or the crankshaft fails, often while drivers are traveling at highway speeds.

The defect is particularly insidious because failures often occur without warning. Owners report symptoms like knocking sounds, hesitation, loss of power, and stalling, sometimes just moments beforea complete breakdown. Many failures have occurred in vehicles with fewer than 10,000 miles on the odometer.

Federal safety regulators have documented over 28,000 field complaints related to these engine failures, with reports linking the defect to 12 crashes and 12 injuries. The lawsuits allege that GM became aware of these problems as early as late 2021 but continued selling affected vehicles without disclosing the defect to consumers.

The AFM/DFM Valve Lifter Defect

The second lawsuit targets a different but equally serious problem with GM's cylinder deactivation technology. To improve fuel economy, GM introduced Active Fuel Management and later Dynamic Fuel Management systems that deactivate some cylinders during light-load driving.

However, plaintiffs allege that the valve lifters in these systems were designed and manufactured with critical flaws. The lifters are made from substandard materials that cannot withstand the stress of repeated activation and deactivation cycles. They are improperly positioned or installed in the engine. They lack adequate clearance to accommodate normal thermal expansion during operation.

As a result, these lifters collapse, causing a cascade of problems: distinctive ticking or knocking sounds from the engine, engine misfires and rough running, shuddering or hesitation during acceleration, unexpected stalling, and debris from failed lifters damaging other engine components.

The problem affects a broader range of vehicles than the L87 issue, potentially impacting over one million vehicles built between 2014 and the present with 5.3-liter L84, 6.2-liter L87, or 6.0-liter L96 V8 engines across GM's entire truck and SUV lineup.

The Recall That Wasn't Enough

In April 2025, GM issued Recall 25V-274, assigned NHTSA campaign number N252494000. This recall affects 597,630 vehicles in the United States, with global figures reaching as high as 877,710 vehicles.

Covered vehicles include 2019-2024 Chevrolet Silverado 1500 and GMC Sierra 1500 pickup trucks, and 2021-2024 Chevrolet Tahoe and Suburban, GMC Yukon and Yukon XL, and Cadillac Escalade and Escalade ESV full-size SUVs, all equipped with the 6.2-liter L87 engine.

GM's remedy involves having dealers inspect each engine. If the engine passes inspection, the owner receives an oil change to a thicker 0W-40 weight synthetic oil, specifically Mobil 1 FS 0W-40 as of February 2026. If the engine fails inspection, which occurs in approximately 3% of cases, GM replaces the entire engine.

However, both plaintiffs and automotive experts have criticized this remedy as inadequate. The thicker oil reduces fuel economy by an estimated 3-4% and limits the effectiveness of the Dynamic Fuel Management system, which was a key selling point. More importantly, the oil change doesn't fix the underlying manufacturing defects in the crankshaft, connecting rods, and bearings; it merely attempts to mask symptoms.

Perhaps most troubling, replacement engines come from the same production runs and contain the same design and manufacturing flaws as the failed units. Owner reports on social media and automotive forums describe situations where replacement engines have also failed, sometimes after just a few thousand miles.

Even GM's claim that engines built after June 2024 have been fixed has proven questionable. Reports continue to emerge of failures in 2025 and 2026 model year vehicles, including one documented case of a 2026 GMC Yukon experiencing complete engine failure at just 1,500 miles.

Federal Regulators Investigate Further

The National Highway Traffic Safety Administration has not been satisfied with GM's recall remedy. An initial Engineering Analysis (EA25007) was expanded in October 2025 to examine a broader scope of failures.

More significantly, in January 2026, NHTSA opened a new Recall Query investigation (RQ26001) specifically examining post-remedy failures. This probe was triggered by 36 complaints of engines breaking down even after receiving the recall remedy, including engines that had been completely replaced.

This investigation could force GM to implement a more comprehensive recall with a redesigned fix, potentially including redesigned engine components or a complete engine replacement program using genuinely improved engines.

Legal Claims and What Plaintiffs Are Seeking

The consolidated lawsuits assert multiple legal claims against General Motors:

• Breach of Express Warranty: GM promised reliable, durable engines, but delivered defective products that fail prematurely.Breach of Implied Warranty of Merchantability: The vehicles are not fit for their ordinary purpose of safe, reliable transportation.

• Fraudulent Concealment: GM allegedly knew about the defects but actively hid this information from consumers to continue sales.

• Violations of State Consumer Protection Laws: GM's conduct allegedly violates consumer protection statutes in multiple states that prohibit deceptive trade practices.

• Unjust Enrichment: GM profited from selling defective vehicles while owners bear the costs of repairs, lost value, and safety risks.

Plaintiffs in the Powell case are seeking comprehensive relief, including full reimbursement for out-of-pocket repair expenses, compensation for lost vehicle value, payment for alternative transportation during repairs, vehicle buybacks for those who no longer trust their vehicles, installation of genuinely redesigned engines, and punitive damages to deter future misconduct.

The Harrison case similarly seeks damages, repairs, and an injunction requiring GM to disclose the lifter defect and provide a permanent fix at no cost to owners.

Potential Financial Impact

The financial stakes are enormous. Industry analysts estimate that if the class actions are certified and succeed, GM could face liability in the range of $500 million to over $1 billion for the L87 engine cases alone.

The recall itself has already cost GM an estimated $138 million to $175 million. If NHTSA forces an expanded recall requiring the replacement of all potentially affected engines with redesigned units, costs could balloon to several billion dollars.

For comparison, a similar class action lawsuit over oil consumption in older GM 5.3-liter engines (Siqueiros v. General Motors LLC) settled in October 2025 for $150 million, covering 2011-2014 model year vehicles. That case resulted in average payments of approximately $3,300 per affected owner, with $57 million going to attorney fees.

Given that the current L87 lawsuit potentially affects hundreds of thousands of more expensive vehicles with more severe defects and documented safety risks, the eventual settlement or judgment could be significantly higher.

Impact on American Consumers and the Auto Industry

These lawsuits have far-reaching implications beyond just GM truck and SUV owners.

For Current Owners: If you own an affected vehicle, you face safety concerns from potential sudden engine failure, significant depreciation as the defects become more widely known, expensive repairs that may not be covered by warranty if your vehicle is out of coverage, and uncertainty about whether the recall remedy actually fixes the problem.

For Used Car Buyers: These vehicles are flooding the used market as some owners try to sell before problems emerge or worsen. Buyers face risks of purchasing vehicles with hidden defects and declining resale values.

For GM: The automaker's reputation for reliability is taking a significant hit at a time when it's trying to compete with Japanese and Korean manufacturers known for bulletproof V8 engines. There is speculation that GM may be forced to eliminate or significantly redesign its Dynamic Fuel Management system—rumors suggest the 2026 Silverado may drop DFM entirely.

For the Industry: These cases highlight tensions between fuel economy regulations and traditional engine durability, potentially influencing how other manufacturers approach cylinder deactivation technology.

Current Status of the Lawsuits

The Powell v. General Motors LLC case is in the discovery phase, with both sides exchanging documents and evidence. The case is proceeding toward a class certification motion expected in late 2026. If certified, the lawsuit would officially become a class action representing all similarly situated owners, dramatically increasing GM's potential exposure.

The Harrison et al. v. General Motors LLC case survived GM's motion to dismiss in January 2023, allowing the core claims to proceed. The class certification hearing, originally scheduled for December 2025, has been extended into 2026 as discovery continues.

GM has consistently denied the allegations in both cases, attributing engine failures to isolated manufacturing issues or owner maintenance practices. However, the volume of complaints, consistency of failure patterns, and NHTSA's ongoing investigations suggest more systemic problems than GM acknowledges.

Neither case has reached settlement negotiations that have been made public, and GM appears to be taking a defensive posture, likely hoping to avoid the precedent that a major settlement would create.

What Owners Should Do

If you own a vehicle potentially affected by these defects, consider taking the following steps:

• Document everything related to your vehicle's performance, including dates, mileage, and descriptions of any unusual sounds, hesitation, or warning lights. Keep all service records, even for routine maintenance. If you experience engine problems, have the vehicle towed rather than driving it, as continued operation could void warranty coverage or create safety hazards.

• If your vehicle is subject to the recall, have the remedy performed at a dealership and keep all documentation. However, understand that the recall remedy may not fully resolve the underlying defect.

• Consult with an attorney experienced in automotive defect cases. Many of the law firms involved in these class actions offer free case reviews. Even if you haven't experienced a failure yet, you may be entitled to compensation for diminished vehicle value.

• Report your experience to NHTSA through their website at safercar.gov. These reports create an official record and help regulators assess whether additional action is needed.

What Happens Next?

These cases are likely to proceed through 2026 and potentially into 2027 before resolving. Key developments to watch include NHTSA's Recall Query investigation results, which could force an expanded recall, class certification decisions in both cases, which would dramatically increase pressure on GM to settle, discovery revelations about what GM knew and when, and potential settlement negotiations if GM's litigation position weakens.

For GM, the path forward is uncertain. The company faces a choice between fighting these cases to the end, risking massive judgments and continued reputational damage, or negotiating comprehensive settlements that could cost billions but draw a line under the controversy.

For owners, the wait continues, along with the anxiety of wondering whether their engine will be the next to fail catastrophically.