U.S. auto safety regulators are probing General Motors Co. over concerns that more than 870,000 of its full-size pickup trucks and SUVs face the risk of engine failure.

The National Highway Traffic Safety Administration’s Office of Defects Investigation has begun looking into engine failures involving an estimated 877,710 vehicles from GM. The vehicles are full-sized trucks and SUVs equipped with the 6.

The National Highway Traffic Safety Administration is investigating a potential issue with certain models with V8 engines for engine failure

Complaints received by the agency allege a bearing failure that may result in either an engine seizure or a breaching of the engine block. GM said it is cooperating with the agency.