Vauxhall staff have returned to work after an unofficial walkout at the Ellesmere Port factory in a dispute over possible job cuts.
The walkout halted production at the Ellesmere Port plant
A walkout over news that parent firm GM could axe 1,000 jobs at the Cheshire site halted production on Thursday.
Negotiations between unions and management ended without resolution on Thursday and will resume next week.
GM has said it wants to improve efficiency at the site, but no decision had been reached about its future.
The walkout on Thursday was triggered after GM Europe's chief executive Carl-Peter Forster made comments, which workers thought implied it was easier to sack staff in the UK than elsewhere.
Earlier in the week Mr Forster told journalists: "We know, thank God, that the English labour market is more capable of absorption than, let's say, the German or the Belgian markets."
John Cooper of the Transport & General Workers union (T&G) said workers had downed tools to send a "clear message" to the company that unions and workers wanted clear and honest talks over plans for the site.
"But we also want to make it clear that we want to keep Ellesmere Port working," he added.
However, he did add that the union was "not too hopeful" about the situation.
GM Europe has said it is determined to handle the situation "as socially responsibly as possible".
"For the future, it is important for Ellesmere Port that everyone works together to meet the continuing demand for the Astra," it added in a statement.
"We look forward to working together to give the plant the best opportunity to compete in the automotive industry in the long term."
'Easiest to sack'
Unions claim GM Europe president Carl-Peter Forster said the company wants to cut one shift from the plant, which it says would lead to 1,000 job losses, representing about one-third of the plant's workforce.
"We would have expected better from such a senior executive of the company," said Roger Maddison, of the Amicus union.
"His comments are extremely unhelpful during critical ongoing negotiations between the company and trade unions in Germany."
Tony Woodley, general secretary of the T&G, said "British car workers are among the best in Europe, but they're the easiest to sack".
"These decisions are not led by business logic, but by the fact that our laws don't protect our workers," he added.
A day before the walkout, Amicus has expressed its opposition to the UK being singled out for job cuts saying it made "no sense".
Instead Amicus said it wanted cuts to be spread throughout Europe's Astra plants in Belgium and Germany.
Amicus said it had put several proposals to the firm which were still being considered, in an attempt to avoid job cuts.
General Motors is assessing production levels at three Astra factories in Europe.
Aims to reduce costs are part of the ailing car firm's wider restructuring plans, which include cutting 12,000 jobs across the continent.