Red Bull Racing's 2010 engine plans are on hold until after it finds out about Renault's Formula 1 future in next week's FIA World Motor Sport Council meeting, AUTOSPORT has learned.
The Milton Keynes-based team had hoped to make a switch to Mercedes-Benz for next year, but that ambition cannot move forward because the FIA has not yet granted the German manufacturer the right to supply an extra team beyond McLaren, Brawn GP and Force India.
Furthermore, Mercedes-Benz cannot increase its supply of power units without approval from partner McLaren - something that has not yet been forthcoming amid the fallout from the plans for Mercedes to buy into Brawn GP.
Mercedes-Benz motorsport boss Norbert Haug said at last weekend's Italian Grand Prix that its engine plans were now resting on approval from McLaren and the FIA, having originally hope to announce the engine plans in Monza.
"McLaren and us are exclusive partners," said Haug. "Without the allowance, without the co-operation....we are not ready [to announce the plans]. Whether we will have yet another customer team, that is not decided yet. It needs to be decided with the FIA as well."
That situation has left Red Bull Racing unable to finalise its engine plans for next year. The situation is further complicated by the fact that current partner Renault may not be in F1 in 2010 if it is banned or chooses to quit in the aftermath of the Singapore GP race-fix allegations.
The uncertainty about engines is a big problem for Red Bull Racing, after its progress into world championship challengers this year shows that its ambition is now for titles. Accepting a second-rate engine deal is not on the team's agenda - which is why it has only been considering the Mercedes-Benz or Renault route.
Red Bull Racing boss Christian Horner has said that he will not worry more about its engine situation until after next week's FIA World Motor Sport Council hearing into Renault.
"Obviously we need to wait for the scenario of the 21st," Horner told AUTOSPORT. "We have a strong relationship with Renault, who have been a very good partner of the team for the last three years, and we will wait and see how things pan out."
The imposition of an engine freeze in F1, allied to restrictive design rules, makes the packaging of different engine types much easier to sort out than in the past - as Brawn GP showed this year when it installed a Mercedes-Benz power-unit on the eve of the campaign.