GM class action lawsuit overview:
- Who: Plaintiff Robert Hubof filed a class action lawsuit against General Motors LLC.
- Why: He claims GM concealed an oil cooler defect in its heavy-duty diesel trucks and denied warranty coverage for the resulting engine damage.
- Where: The GM class action lawsuit was filed in Michigan federal court.
A new class action lawsuit claims General Motors concealed a defect in the oil coolers of its heavy-duty diesel pickups and refused to cover the resulting engine damage under warranty.
Plaintiff Robert Hubof claims the oil coolers in 2024 through 2026 Chevy Silverado 2500HD and 3500HD and GMC Sierra 2500HD and 3500HD trucks with the 6.6-liter Duramax diesel engine are prone to crack during normal driving, with some 2027 models possibly affected.
According to the class action lawsuit, the cooler uses engine coolant to regulate oil temperature while keeping the two fluids separate. When it cracks, pressurized oil can escape into the cooling system or leak from the truck, starving the engine of lubrication and potentially causing engine seizure or catastrophic failure.
Hubof argues GM denies full warranty coverage by blaming low oil levels on poor maintenance, often paying only for a new cooler when the engine needs replacing. He claims replacement coolers are equally defective and on national backorder.
“Such denial leaves [the] plaintiff and class members responsible for tens of thousands of dollars of repairs for damage caused by the oil cooler defect,” the GM class action lawsuit says.
Hubof wants to represent a nationwide class of all persons or entities in the United States that purchased or leased an affected truck, other than for resale, and an Idaho class.
Plaintiff quoted more than $41K after oil cooler failure in Chevy Silverado
Hubof claims he bought a new 2024 Chevrolet Silverado 2500 HD in December 2023. In June 2025, with about 16,453 miles on the odometer, he heard a loud bang and found oil in the coolant bottle leaking beneath the truck, he says.
A GM technician found the cooling system filled with engine oil and metal debris in the oil system. The truck was not repaired under warranty, and Hubof instead received a repair quote of $41,319.79, the GM class action lawsuit alleges.
Hubof claims GM knew of the problem before his purchase, noting its customer service team responded to a 2024 Sierra owner’s oil cooler complaint online in November 2023. He also cites an urgent August 2024 service update ordering dealers to hold affected trucks and a March 2025 bulletin acknowledging oil in coolant “may be caused by a leaking engine oil cooler.” GM nonetheless marketed the trucks as “reliable” and “durable,” he says.
The class action lawsuit accuses GM of breach of warranty, fraudulent concealment, unjust enrichment and violations of Idaho consumer protection law.
The plaintiff demands a jury trial and requests declaratory and injunctive relief, including a court-supervised repair program, and an award of damages for himself and all class members.
In another GM class action lawsuit, a group of consumers alleges the company knowingly sold a wide range of vehicles, including Chevrolet, GMC and Cadillac models, with defective 10-speed transmissions.
Have you had oil cooler problems with a heavy-duty GM diesel pickup? Let us know in the comments.
The plaintiff is represented by E. Powell Miller and Dennis A. Lienhardt of The Miller Law Firm P.C., Matthew D. Schelkopf and Joseph B. Kenney of Sauder Schelkopf LLC and Bonner C. Walsh of Walsh PLLC.
The GM class action lawsuit is Hubof v. General Motors LLC, Case No. 2:26-cv-13622, in the U.S. District Court for the Eastern District of Michigan.
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