Carlos Sainz says McLaren are “running out of things to try” having still not solved his Formula 1’s car’s cooling problem despite giving him a new chassis for the Spanish Grand Prix.

The Spaniard had to run a different aerodynamic set-up over the 70th Anniversary Grand Prix weekend at Silverstone due to his MCL35 running hotter than the car of teammate Lando Norris.

In a bid to try and address the cooling issue for his home race at this weekend’s Spanish Grand Prix, McLaren swapped Sainz’s chassis. But after running with his new monocoque during Friday practice in Barcelona, Sainz conceded the change had failed to rectify the problem.

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“At the moment, we haven’t really solved the issue, we still see some discrepancies across the two cars,” Sainz said.

“My car, obviously we have [a cooling issue] and we’re having to run with more cooling on the car which obviously costs more lap time around here. So still not fully into the bottom of the problem – we need to keep searching.

“It’s a big question mark that we haven’t found [the answer to] and we’ve changed pretty much everything on the car and we’re starting to run out of things to try.

“Hopefully we can find the last thing or the main thing which will give us the final answer, but at the moment it’s tricky.”

Sainz, who has a best result of sixth place in Spain, finished 11th in opening practice on Friday morning before improving to lift himself inside the top-10 with a lap good enough for the seventh-fastest time in the afternoon. 

“We don’t see the blistering we saw in Silverstone so there’s potentially a bit more scope on the tyres, a bit more margin, but we do see quite a lot of degradation – we see quite a lot of overheating on the tyres – so it’s going to be a tricky weekend," he explained. 

“And at the moment we are still not on top of the issues with the tyres and we want to keep improving for the race."