McLaren issues revealed as testing cut short in Barcelona

McLaren have revealed that there were some issues with their new 2026 F1 car during the fourth day of testing in Barcelona, causing them to cut the day short.

The team were on their second of an allotted three days of testing per team across this week's five-day Barcelona private shakedown, and Australian driver Oscar Piastri took to the track for the first time on Thursday.

His world champion team-mate Lando Norris had taken Wednesday's running, with the pair set to split the morning and afternoon sessions on their final day on Friday.

However, Piastri was sat in the garage for most of the afternoon on Thursday, despite the MCL40 supposed to be out on the track getting in as many miles as possible.

Following the day's testing, Piastri and a McLaren team member came out and revealed they had suffered problems with the new car, forced to spend much of the afternoon session attempting to fix it in time for Friday.

"Unfortunately a few issues today," Piastri told F1.com after testing. "We had a fuel systems issue which cut our day a bit short, but I know the team's working really hard to get that fixed and get us back out for as many laps as we can tomorrow.

"Definitely the first few things, trying to iron out these bugs, trying to find the problems, they're all completely different cars, completely different engines to what we've had for the last three or four years so that's part of what this test is about and I think we've already identified a few things we can try and improve on the car to make it feel a bit nicer."

Meanwhile, technical director Mark Temple added: "So, obviously there’s positives to take away. We’ve gone out, we’ve got a good understanding of where the car is from a baseline point of view, but obviously we’ve had some issues. We’ve not been able to do all the running that we would like, we discovered a fuel system problem and the car’s very complex.

"So we decided to bring back into the garage, strip it down fully, understand where the problem is coming from. Obviously, that means we’re not back out on track at the moment."

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Are McLaren struggling compared to rivals?

McLaren opted not to take to the track until Wednesday this week, and following a disrupted Thursday, they have not got in as many laps as some of their competitors, including Mercedes.

The Brackley-based outfit have completed over 400 laps during this five-day shakedown in Barcelona, and have had very few reliability issues, with George Russell topping the timesheets so far, suggesting their W17 is also fast.

It is notoriously difficult to establish the competitive order based off pre-season testing, but there's no doubt McLaren look like they'll have more competition to retain their titles this year than they did in 2025.

Last year, the team dominated, claiming 14 of 24 grand prix victories throughout the season and wrapped up the constructors' championship as early as October.

With the new regulations, however, it's likely the competitive order for the season-opening Australian Grand Prix will be completely different to the competitive order at the season-ending Abu Dhabi GP, with different teams developing their cars at different rates as everybody gets used to the new rules.

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