Red Bull engine decision still looming

After the Brazil GP deadline came and went, Red Bull is now expected to finalise its choice of engine supplier for 2010 by next weekend's Abu Dhabi season finale.

The energy drink company's motor sport adviser Helmut Marko said at Interlagos that the decision had been delayed for about another week, but Germany's Auto Motor und Sport reports that Abu Dhabi is actually the new deadline.

The magazine said the FIA has now approved the application for a fourth Mercedes engine supply, but the German marque's exclusive partner McLaren is currently vetoing the Red Bull deal.

It is said that McLaren's decision hinges on Mercedes' precise plans for a closer involvement with Brawn, but Marko said: "Time is running out."

With Mercedes out of the picture, Red Bull's choice is between either staying with Renault or - like Williams - switching to Cosworth.

Renault, also with a works team, is said to be pushing hard to retain its competitive partner, perhaps promising to bundle a sponsorship deal with the oil company Total.

Cosworth's ace up its sleeve, however, is that it is the only engine supplier allowed to work on its 2010 engine, and the result could be the most powerful V8 in the field next year.

"Engine performance is one thing," said German driver Nico Rosberg, "but in 2010 the fuel efficiency and reliability will play a big role.

"It is very difficult for Cosworth to master all three disciplines in so short an amount of time," he added.

Moreover, Red Bull team boss Christian Horner says he has been impressed with the Renault engine in the wake of the reliability problems of earlier this season, with well-used units serving his drivers well at recent events.