Trucks come off the assembly line at GM's Chevrolet Silverado and GMC Sierra pickup truck plant in Fort Wayne, Indiana, in July 2018. (Photo: John Gress Media Inc/Shutterstock.com)

Beasley Allen of Atlanta and Montgomery, Alabama, is part of a legal team that has obtained class action certification in a case against General Motors Co. over allegations of faulty piston rings causing engine burnout.

The complaint was filed in 2016 in U.S. District Court for the Northern District of California and has been amended five times since then. Judge Edward M. Chen issued a 93-page order Friday certifying class claims for three bellwether plaintiffs in California, North Carolina and Texas.

The allegations have "evolved," Chen said, but "the core facts of this case remain the same." The complaint has alleged that more than 830,000 model year 2011-2014 GM pickups and SUVs suffer from an oil consumption defect caused by faulty piston rings. These piston rings "do not maintain sufficient tension to keep oil in the crankcase," and instead oil burns off, and engines fail, sometimes leaving drivers stranded on roads, the complaint alleged.

The plaintiffs have also alleged that GM knew about the defect but failed to address it effectively, even using a repair that didn't work. "Thus, despite the fact that GM knew that the piston cleaning procedure was ineffective by February 2010, it still directed servicers of GM vehicles to complete the procedure as part of the recommended response to oil consumption problems without addressing the root problem," Chen said.

"Our clients allege that their GM's Generation Four Vortec 5300 V-8 engines consume oil in such high volume that they foul spark plugs and aggressively wear internal rotating components from inadequately lubricated metal-on-metal contact," the Beasley Allen team said in a prepared statement. "GM's documents and witnesses confirmed that the excessive oil consumption defect lies in piston rings that wore prematurely and allowed oil to migrate into the combustion chambers and burn away."

GM did not have a response.

"We are pleased that the court recognized the severity of this serious engine problem and GM's attempt to cover up the defect," said Dee Miles, head of the Beasley Allen's consumer fraud section. "We're also pleased that Judge Chen viewed the issues in this case as best suited for class-wide treatment."

Miles is handling the case with Clay Barnett, Leslie Pescia and Mitch Williams of Beasley Allen, along with attorneys from Dicello Levitt Gutzler in Chicago, and Andrus and Anderson in San Francisco.

The case is Monteville Sloan, et al. v. General Motors LLC, Case 3:16-cv-07244-EMC.