Spielberg, Austria - Formula One champions Red Bull has called for change at engine partner Renault after an 'unacceptable' performance in Sunday's Austrian Grand Prix.
Quadruple world champion Sebastian Vettel retired from the race at Spielberg with an electronics problem, his third failure to finish this season due to an issue with the new V6 turbo hybrid power unit.
Team principal Christian Horner told reporters: “The reliability is unacceptable. The performance is unacceptable. There needs to be change at Renault.
“It can't continue like this. It's not good for Renault and it's not good for Red Bull.”
The champion, winner of both titles for the past four years with Renault power, is now 158 points behind leader Mercedes after eight races.
Australian Daniel Ricciardo won the previous Canadian Grand Prix but was a distant eighth on Sunday.
Renault Sport F1's deputy managing director Rob White said the manufacturer, which started the year well behind Mercedes on performance, knew what had to be done and progress was being made.
He said: “The anxiety that Christian feels, and the frustration he feels after a result that is not at the full potential of the performance of car and power unit, is completely understandable and shared by us.”
“We know what is expected of us and individually and collectively we must buckle down in the right direction.”
Horner made clear Red Bull would stay with Renault next season, when Honda are due to make their return as partners to McLaren, but he wanted to see a big improvement.
“We need to work together as partners, Horner said. “There will not be another engine in the back of the car next year, but we want to be competitive and we want to run at the front.
“Something needs to happen because whatever's being done there at the moment isn't working.
“It's not our business, it's not our responsibility. We're the end user and it's just frustrating that it's not where it needs to be at the moment,” he added.
The only other engine manufacturers are Mercedes and Ferrari.