Former grand prix driver David Coulthard has warned not to take Red Bull's threat of leaving Formula One lightly.
Earlier this week, Red Bull advisor Helmut Marko told Austrian media the energy drinks company could leave the sport because the engine formula was wrong and the technical rules too complex.
"We will evaluate the situation again as every year and look into costs and revenues," said Marko. "If we are totally dissatisfied we could contemplate an F1 exit.
"The danger is there that Mateschitz loses his passion for F1."
If Red Bull go, they take with them four cars.
Red Bull has also called for the FIA to act on Mercedes' dominance, but the team has found little support from its rivals.
Coulthard, a former Red Bull driver, says the team's threat must be taken seriously.
"These guys are empowered and are in control, so they are not saying anything that they don't have the position to act on," Coulthard told Motorsport.com.
"So you take any of these guys seriously because history has shown that manufacturers come and go, teams can and go, and if Red Bull go, they take with them four cars, and you can't afford to just close the door.
"They probably wouldn't. They would probably try to make sure there was something for the mechanics and the engineers."
Trouble with Renault
The Scot also suggested the fact that Red Bull has been openly critical of Renault's performance shows their relationship is strained.
"It's not against Mercedes, I think, what they are saying, and it's obviously not great for the relationship with Renault to be so negative," Coulthard added.
"We don't know what's been going on behind closed door. They do what they think it's the right thing to do. Clearly if you don't feel you are making progress privately then maybe you take it publicly. It is what it is.
"Renault has to improve, Red Bull has to improve, and all teams have to improve, otherwise Mercedes will win the championship easily."