McLaren says F1 test mileage at Jerez "a huge relief"

Fernando Alonso and Jenson Button could only manage six laps each amid myriad problems on Sunday and Monday, but McLaren was adamant it made a breakthrough at the end of the second day.

It proved that was the case by taking to the track immediately when Tuesday's session began, with Alonso completing 32 laps before a water leak forced him to park for the afternoon.

When asked by AUTOSPORT how important it was to begin running straightaway on Wednesday, Boulier replied: "Very important, and firstly a huge relief.

"Last night we were a little bit happier after Jenson's last lap because we believed we had fixed the issues, but sometimes you fix one problem and then another one is coming.

"This morning it was just a relief to see the car get out at nine o'clock and then run faultlessly for a few hours."

Boullier said Tuesday's problem was not related to the electrical issues that had plagued the previous days.

"It was a third-party component that caused a water cooling leak and we had to take the engine off and open everything to change it because it's in the middle," he explained.

"We could have maybe run half an hour at the end, but we decided to stop and do it properly for tomorrow.

"The main issues are now away."

Boullier admitted that McLaren had hoped to get much more done at Jerez, but he said the team was encouraged that elements such as cooling had worked faultlessly once the car was able to do some sustained running.

Asked how much of the team's planned work had been achieved so far, Boullier replied: "Maybe less than 50 per cent.

"But it's better than nothing, and at least operationally we have covered everything we wanted.

"The good thing is the car is running 10 laps in a row, so we have no design, concept or architecture issues with the car."

He also reckons the early signs about car behaviour and handling are encouraging.

"The driver comments were very, very positive," said Boullier.

"Fernando said the car is really reacting well and really stable.

"You could see from the pitwall that the car was stable into Turn 1, and that was when Mercedes was out as well."