Coulthard optimistic of engine reliability

The team had major cooling problems before the season started, and they had not completed a full Grand Prix distance before the Bahrain Grand Prix.

Coulthard was forced to change his Ferrari engine following the Bahrain race, and retired with a hydraulics problem in Malaysia.

The Scot, however, had a trouble-free Australian Grand Prix and scored his first point of the season with eighth place.

After covering over 100 laps in testing at Barcelona on Thursday, the Red Bull driver believes the team's reliability problems are now behind.

Coulthard, nonetheless, admitted he is somewhat worried the low temperatures could pose a problem for his team at the San Marino Grand Prix.

"We did fair amount of laps and we seem to be on top of the reliability issues and just like in Valencia we are getting more information here," Coulthard told autosport.com. "Balance wise we have got what we got so let's see how it pans out in the race here.

"We did some work in general as well as some specifically here, so let's see hot it works in Spain. As for Imola the key is temperature. I think it is likely to be lower than here and some of us have struggled with the temperature so let's wait and see.

"In any case we did what we can. It was a good test really."