Drivers who’ve lived with GM’s L87 V8 already know the drill. Some watched their high-dollar trucks or SUVs stall without warning. Others sat in dealership lounges while technicians drained factory oil. They poured in the thicker replacement fluid GM recommended, calling it a fix. They left with the same engine and a sense that they’d just received the mechanical equivalent of a compression sleeve on a broken arm.

The lawsuit over these failures was filed last year. Now it’s pushing forward, arguing that GM’s remedy never actually addressed the real problem.

The class action comes from Illinois owner Ronald S. Hermanowicz, who bought a new 2024 GMC Sierra 1500 in June 2024

Nine months later he reportedly heard a loud ticking before the engine quit.

At the dealership, technicians found spun rod bearings that had damaged the connecting rods and crankshaft, sending metal fragments through the system. His Sierra needed a replacement L87 engine, plus new oil cooler lines and a radiator.

He waited three weeks on the turnaround. While he didn’t pay for those repairs, he did pay $405 to file with the class action lawsuit seeking more than $5 million.

Filed in federal court in Michigan, the case covers 2019 to 2024 GM cars

Including the Chevrolet Silverado 1500 and GMC Sierra 1500, along with 2021 to 2024 Cadillac Escalade and Escalade ESV, Chevrolet Tahoe and Suburban, and GMC Yukon and Yukon XL. 

The complaint claims the engines suffer from defective connecting rod bearings and crankshaft dimensions that fall outside intended specifications. He said GM has been aware of the issue since at least 2021.

The filing points to more than 28,000 reports to GM and regulators regarding L87 engines, with over 14,000 involving loss of propulsion

That’s according to CarComplaints.com. 12 crashes and 12 injuries have been reported. In some cases, connecting rods reportedly punched through the engine block.

GM previously recalled nearly 600,000 vehicles to address the problem. Under that recall, if dealers found no clear defects in the crankshaft or camshaft, they were instructed to replace the factory oil with a heavier formulation to reduce bearing wear.

The lawsuit claims that approach increases internal drag, hurts power and fuel economy, and affects resale value. He argued it doesn’t resolve the root defect.

The case is being handled by Meyer Wilson Werning Co., LPA, and Kaplan Fox & Kilsheimer LLP.