GM Valve Lifter Lawsuit: Affected Engines, Costs, and 2026 Status

The GM valve lifter lawsuit, Harrison, et al. v. General Motors LLC, is an active class action in the U.S. District Court for the Eastern District of Michigan alleging that millions of GM trucks, SUVs, and performance cars were sold with defective valve lifters tied to the company’s Active Fuel Management (AFM) and Dynamic Fuel Management (DFM) cylinder-deactivation systems. Filed in December 2021, the case covers 5.3-liter, 6.0-liter, and 6.2-liter V8 engines in Chevrolet, GMC, and Cadillac vehicles from model year 2014 forward. As of mid-2026, the class has not been certified, no trial date is set, and no settlement is on the table.¹

What the Lawsuit Claims Is Wrong With the Engines

AFM and DFM save fuel by shutting off cylinders under light load. Specialized hydraulic lifters collapse on command, controlled by oil pressure routed through the valve lifter oil manifold. The complaint alleges these lifters and the valvetrain around them are poorly designed and built from substandard materials, so they fail during normal driving.²

The plaintiffs point to several engineering issues. Lifter bores are allegedly too narrow for the lifters to move freely. Internal locking pins wear out from constant cycling between cylinder modes. The engine control software is programmed in a way that mistimes valve events. The system also fails to account for thermal expansion differences between the lifters and the block, and for the high oil pressure the AFM lifters need to work.²

When a lifter collapses or sticks, damage spreads. A stuck lifter grinds against the camshaft lobes and sheds metal into the oil. Pushrods bend from uneven pressure. Valve springs fail early. Rocker arm bearings lose their needles.³ Owners typically report engine ticking, misfires, rough idling, check-engine lights, and in severe cases a total loss of power at highway speed. The suit says these failures can escalate to catastrophic engine damage that requires a full engine replacement, and that GM’s dealer repairs often leave damaged parts in place, producing repeat failures after the factory warranty has expired.²

Which Vehicles and Engines Are Covered

The lawsuit covers GM vehicles from model year 2014 through the present with 5.3-liter, 6.0-liter, or 6.2-liter V8 engines using AFM or DFM.¹ The models named include:

Chevrolet Silverado and Silverado 1500, Suburban, Tahoe, Camaro, Camaro SS, Corvette, and Avalanche
GMC Sierra and Sierra 1500, Yukon, and Yukon XL
Cadillac Escalade and CTS-V²

The newer DFM system in the L84 5.3-liter and L87 6.2-liter engines, found in redesigned Silverado 1500 and Sierra 1500 trucks starting around 2019, is also included. DFM can deactivate any combination of cylinders across all 16 lifters, and the plaintiffs contend this makes it more failure-prone than the older AFM design, which shuts off a fixed set of cylinders.³

What Failures Cost Owners

Basic lifter replacement runs $1,000 to $2,500. When the camshaft or other internals are damaged, quotes climb to $5,000 to $11,000 for a full cam-and-lifter job or an engine replacement.⁴ In some 6.2-liter DFM cases with oversized lifter bores, the block itself is considered irreparable, so a complete engine swap is the only option.⁵

GM has not broadly covered these repairs. The company has offered an extended warranty to owners who have had at least two related repairs,⁴ but many owners report failures shortly after the standard warranty expires and difficulty getting help. One reported instance involved a dealership persuading GM to cover half the cost of a new engine, which appears to be an exception.⁵

Some owners have turned to aftermarket disablers. Plug-in OBD-II modules from companies such as Range Technology keep the engine in full V8 mode and prevent AFM or DFM from activating. They cost roughly $250 to $600 and are marketed as reversible. More aggressive fixes physically delete the AFM or DFM hardware by swapping in a non-deactivating camshaft, lifters, and related parts.⁶

GM’s Own Service Bulletins Acknowledge the Problems

GM has not issued a broad federal recall for lifter failures, but its own technical service bulletins describe the failure modes in detail. TSB 15-06-01-002N, updated in February 2023, addresses “Engine Misfire/Tick Noise” in 2014–2023 vehicles with 5.3-liter and 6.2-liter engines. It identifies AFM lifters that are “mechanically collapsed and/or stuck,” internal locking pin damage from oil aeration, and bent pushrods.⁷

TSB 19-NA-218 covers engine ticking caused by lifters that fail to receive enough oil during cold starts. It applies to various 2019–2022 Cadillac, Chevrolet, and GMC models and instructs technicians to run cylinder deactivation tests, check for bent pushrods, and replace lifters on affected banks.⁸ The bulletins matter to the litigation because they show GM was internally documenting the failure patterns the lawsuit describes.

Where the Case Stands in 2026

The case is before Judge Laurie J. Michelson in the Eastern District of Michigan.⁹ It has moved slowly. In January 2023, the court ruled on GM’s motion to dismiss and found that what the plaintiffs called a single “Valve-Train Defect” was really three distinct issues: rocker arms shedding needle bearings, premature valve spring failure, and lifter collapse or sticking. No individual plaintiff had shown all three failures, a point the judge noted could complicate class certification.¹⁰

In March 2026, the plaintiffs asked to split the case into two, one for older AFM vehicles and one for newer DFM vehicles. Judge Michelson denied the motion, faulting the timing as coming “four years after the suit was filed and almost three years since the Court issued that warning” about the possibility of splitting. GM had also opposed the split, arguing it would create duplicative discovery and possibly two trials.¹¹

The case remains one action covering both AFM and DFM claims. Discovery continues, and the litigation is heading toward class certification briefing and dispositive motions. No trial date has been set, and no settlement is under discussion.¹¹ If you own an affected vehicle and have not opted out, you remain part of the putative class and do not need to file anything at this stage.

A Separate NHTSA Investigation Into the 6.2-Liter V8

The National Highway Traffic Safety Administration opened a preliminary evaluation in early 2025 into engine failures in roughly 877,710 GM vehicles with the L87 6.2-liter V8. The probe covers 2019–2024 Chevrolet Silverado, GMC Sierra, Chevrolet Tahoe, Chevrolet Suburban, GMC Yukon, and Cadillac Escalade models. NHTSA had received 39 complaints and additional early warning reports describing bearing failures that led to engine seizures or connecting rods breaching the block.¹² This investigation is separate from the Harrison lawsuit and focuses on bearing failures rather than lifter defects, though it involves the same engine family and overlapping models.

1
GM Lifter Lawsuit. Harrison, et al. v. General Motors LLC
2
ClassAction.org. Cadillac, Chevy, GMC Valve Train Systems Hampered by Defect, Class Action Claims
3
EGR Performance. Lifter Failure Symptoms
4
Lemon Law Aid. Chevy Silverado Engine Lifter Issues
5
GM Authority. GM Lifter Failures: Huge Issue or Blown Out of Proportion
6
Range Technology. AFM/DFM Disabler
7
NHTSA. GM Service Bulletin 15-06-01-002N
8
NHTSA. GM Service Bulletin 19-NA-218
9
GM Authority. GM Engine Valve Lifter Lawsuit Plaintiffs Denied Motion to Sever by Judge
10
Justia. Harrison et al v. General Motors, LLC, Opinion and Order
11
Pickup Truck Talk. Federal Judge Denies Motion to Split GM Lifter Lawsuit Over AFM/DFM
12
Top Class Actions. NHTSA to Investigate General Motors Over Engine Failure Complaints