Red Bull will consider billing its engine supplier Renault, Dr Helmut Marko revealed on Friday.
Already this week, the reigning world champion team's outspoken Austrian director has hinted he would like to entice Volkswagen into F1.
"We have to decide on our future engine partner then," he told Germany's Sport Bild, referring to the deadline of the team's home Austrian grand prix next month.
Renault had a horror start to the new turbo V6 era, only recovering competitiveness due to joint efforts with the two Red Bull-owned teams, including Faenza based Toro Rosso.
Marko suggested to Bild newspaper on Friday that it has cost the energy drink company a lot of money.
"It would be irresponsible to talk now about exact figures," he said. "But it's a long list of things lost because Renault has not worked well.
"The season's not over yet. At the end, our financial department will make an account. Then we will see what loss we have made by Renault," said Marko.
And he suggested a monetary loss is not the only concern. "The image damage is already beyond repair," said Marko.
A Renault spokesperson declined to comment.