Last Friday (Jan 30) 230 employees of the supplier Karmann in Osnabrueck staged a two-hour walkout.
The result was that a total of 83 Mercedes CLKs, Chrysler Crossfires and Audi A4 convertibles could not be finished.
Top of this week's strike (from February 2) schedule are the regions of Bavaria, Baden-Wuerttemberg and Lower Saxony.
Bosses of the IG Metall union threatened a "Bavarian Bosch day" during which all Bosch locations in Bavaria will go on strike.
Strikes are also planned at the BMW plants in Munich, Dingolfing and Regensburg.
In Lower Saxony IG Metall plans "a powerful wave of strikes" at Conti Teves (Gifhorn), Bosch Elektronik (Salzgitter), Wabco (Hanover) and at Dana and TRW (Barsinghausen). Blaupunkt in Hildesheim is another of the union's targets.
IG Metall chiefs in Baden-Wuerttemberg announced warning strikes at Porsche and DaimlerChrysler.
Mercedes-Benz in Mannheim and Sindelfingen and Audi in Neckarsulm already were hit by strikes last week.
IG Metall, Germany's largest industrial union, is staging short strikes across the country to pressure employers over pay and working hours.
The union says it will not accept employer demands for longer working hours. The union is also upset at the employers' pay offer that falls well short of the 4 percent rise it is claiming for Germany's 3.5 million engineering workers.
Some negotiators are now demanding that pay and working hours are negotiated separately.
Klaus Franz, chairman of the Opel works council, said the subject of increasing working hours should become a separate issue from the annual pay negotiations.
"Otherwise the subject will become too complex," he said.