The MCL33 suffered some fire damage when the bolt failed and the exhaust came loose when Stoffel Vandoorne was driving, leading to a lengthy period of downtime.

On Thursday the car has suffered a different issue, with high temperatures at the rear damaging the bodywork due to a hole in a heat shield, although it was cosmetic and not much time was lost.

However, the car continued to run with the same burn-damaged engine cover due to a lack of a replacement.

"It's a stupid bolt that broke in the exhaust," said Boullier of the first issue.

"So it was a £2 problem which cost us a lot of track time, because everything was burned after in the back of the car, so we had to rebuild the gearbox and the back end.

"So nothing else than this. It didn't cost us much to revise the design, it's more about the track time we lost.

"As you can see the design is still the same and the car is still running."

Regarding today's problem, he added: "Cooling is the first matter that every team is managing in the first week of testing.

"In a case where you have a new engine partner, you might have some sort of heat soak pocket in the car. Nothing else, to be honest.

"We can see on the bodywork there are a couple of stripes, but this is just because we have to make sure there are some proper heat shields in place, consider all the heat soak pockets as I said, and make sure we can modify and change the cooling inside the bodywork."

Despite the issue better weather allowed the team to make some good progress with the car today.

"Finally we got rid of bad weather and mechanical glitches in the car so we could follow our programme.

"We obviously adjusted our programme, we have compressed it since three days to give some priorities to some items, but today we are now starting to gather data on aero, and even work on some mechanical changes now.

"So it's a learning process actually, so we'll try to learn as much as we can now."

Unexpectedly McLaren has done a lot of running on Pirelli's new hypersoft tyres, which only be seen at a few races this year.

"It's just because tyre models predicted that if it's too cold this is the only tyre that you can work with," Boullier added.

"It turned out that everybody tried soft or ultrasoft or hypersoft or whatever it is, the one that also worked very well is the medium tyre."

Boullier says the team has clear targets for next week's second test.

"First to do a race distance, and obviously bringing also some live pitstops, which obviously we've given more focus this year, so we have some new equipment and stuff to try.

"So a race distance will be the key next week."