Production of the Chevrolet Impala and Cadillac CT6 at the Hamtramck factory in Detroit has been extended until early 2020.
Both vehicles were due to end production at the facility in June 2019, bring with it the end of production at the plant.
Two other vehicles made at the factory, the Buick LaCrosse and Chevrolet Volt, have already ended their North American production runs.
GM is planning to close three car factories in North America, ending local production of the Chevrolet Cruze.
The Cadillac CT6 will continue to be sold in the US even after production at Hamtramck ends. Its not clear if it will be built elsewhere in the US or imported from China.