General Motors LLC (GM) notified the agency on April 2, 2015, that they are is recalling certain model year 2004 Buick Regal vehicles manufactured April 9, 2003, to June 1, 2003, 2004 Chevrolet Impala vehicles manufactured April 8, 2003, to June 23, 2003, and 2004 Chevrolet Monte Carlo vehicles manufactured April 7, 2003, to June 23, 2003. On May 18, 2015, GM expanded the recall to cover an additional 49,751 2004 Pontiac Grand Prix vehicles manufactured January 6, 2003, to June 25, 2004. In the affected vehicles, the valve cover gasket may leak.