* Halt to run from mid-September to mid-October -sources
* To be second time this year plant has stopped making Volts
* GM confirms the idling, declines to specify how long
DETROIT, Aug 27 (Reuters) - General Motors Co will idle the Michigan assembly plant that makes the Chevrolet Volt for four weeks from the middle of September to the middle of October, plant suppliers and union sources said on Monday.
It will be the second time this year that the plant, which straddles the border of Detroit and the city of Hamtramck, has stopped making Volts.
GM confirmed the plant idling, saying it will continue to “match supply with demand” for both the Volt and the Chevrolet Malibu sedan that is also made at the plant. The automaker declined to specify how long the plant will be closed.
During the shutdown, GM will do some retooling and other work to prepare for production early next year of the 2014 Chevrolet Impala sedan. The plant will begin building preproduction prototypes of the redesigned Impala this fall.
The 2013 Impala is now made at a GM plant in Oshawa, Ontario. Production of the current-model Impala will continue in Ontario through the second quarter of next year, GM said.
The Volt is “doing great” and gaining sales each month and GM officials expect to report strong August sales as well, said GM spokesman Dave Darovitz.
Sales of the plug-in hybrid car are up 272 percent since last year, but are below initial expectations when GM launched the Volt in late 2010, followed by its near-identical version for Europe, the Opel Ampera.
Some 1,200 hourly workers at the Detroit-Hamtramck plant will receive unemployment compensation during the four-week shutdown period, which amounts to about 90 percent of their normal pay, a union source said.
The plant’s single 10-hour shift works four days a week. That single shift will be suspended for four weeks beginning Sept. 17, supplier and union sources said.
GM would not say whether the number of workers will rise once Impala production has fully shifted to the Detroit-Hamtramck plant.
The idling of the plant was reported earlier by the Automotive News.