Head of the D/C works council, Erich Klemm, told Automobilwoche that a decision is needed on whether the planned four-cylinder "world engine" will be manufactured in Untertuerkheim and the heavy trucks engines plant in Mannheim.
Berthold Huber, second in command at IG Metall, wants a clear answer from D/C bosses on the future of production locations and employment of the D/C work force in Germany until 2012.
Last week Mercedes employees protested against Juergen Hubbert's demand for production costs at German plants to be lowered by 500 million euros a year.
Hubbert threatened to move production of the C class from Sindelfingen to Bremen or to a foreign location to add authority to his demand.
Hubbert told Automobilwoche that derivatives of the C class could be scrapped or built with a different partner.
He said that there are potential partners in Finland and Austria. Valmet and Magna Steyr are "theoretical possibilities," said Hubbert.
D/C trade unions have pledged further action to protest job and wage cuts. "There will be production disruptions until the works council and the group's management board have found a solution," said Klemm.
Robert Bosch is threatening to move production of diesel particulate filters from its plant in Feuerbach, Germany, to the Czech Republic unless workers agree more flexible working hours.
Bosch wants the wage bill for the 11,500 employees at the plant cut by up to 17.5 million euros a year.
"The eight Bosch plants in Germany are being put under huge pressure," complained Werner Neuffer, works council chairman at the Feuerbach plant, complained.