DETROIT -- General Motors Corp. will temporarily close all or portions of 23 engine, transmission and parts factories across the US for several weeks because vehicle-making plants also will be idled.

Spokeswoman Sharon Basel said Wednesday it's all because of plans announced two weeks ago to shutter 13 assembly plants for up to 11 weeks to control growing inventory.

The additional closures affect more than 18,000 hourly and salaried workers. Some parts plants will close for eight or nine weeks, while others will see only one product assembly line shut down, she said.

GM is surviving on $15.4 billion in government loans and faces a June 1 deadline to restructure or go into bankruptcy protection. GM announced the assembly plant shutdowns on April 22 and told workers at the parts plants last week and this week.

Laid-off blue-collar workers would still get most of their pay because their United Auto Workers union contract requires the company to make up much of the difference between state unemployment benefits and their wages.

Of the 23 factories, the longest full-plant shutdowns will occur at the Baltimore and Toledo, Ohio, transmission factories, both of which will close for eight weeks. The Willow Run Transmission plant in Ypsilanti Township, Mich., will see one of its assembly lines closed for nine weeks from May 11 through July 13, Basel said.

Nearly all parts stamping plants will see at least partial shutdowns from this week through the normal two-week summer shutdown that ends July 13, Basel said. Engine plant closures vary from two weeks to six weeks.

The nation's largest automaker announced on April 22 that it would temporarily close the 13 assembly plants because slow sales had built up supplies of many vehicles. Those shutdowns will affect 24,000 workers.

At the end of March, GM had a 123-day supply of vehicles across its model lineup, according to Ward's AutoInfoBank.