McLaren Breaks Curfew Again Over Reliability Fears

McLaren used its second of four curfew exemptions on Friday night in Barcelona to carry out precautionary work on both MCL40s, even after setting the pace in practice, as it sought to protect itself against another power-unit reliability setback.

In a team statement, McLaren said it would “use the second of its four curfew exemptions within Restricted Period Three to carry out precautionary work on both MCL40s” and that it would “replace permissible key components to help improve the robustness of the installation and integration of the power unit on both cars.” The team made clear the overnight work was preventative, not a reaction to any issue that emerged during Friday running at the Circuit de Barcelona-Catalunya.

That decision underlined how seriously McLaren still views the problem after a string of Mercedes power-unit related concerns this season. The most recent flashpoint came in Monaco, where Lando Norris stopped on track in Friday practice before retiring from the race with a power-unit problem. Earlier in the year, both Norris and Oscar Piastri were unable to start in China because of pre-race electrical issues, and Norris also needed a new battery in Japan.

McLaren had already carried out what it described as extensive work in Monaco, replacing the wiring harness, changing the ESME pack and making other changes. But further analysis with Mercedes-AMG High Performance Powertrains pointed to a possible installation-side electrical issue, leaving the team unconvinced it had fully removed the root cause. That is what prompted McLaren to strip both cars down again overnight in Barcelona to be absolutely sure the suspected problem had been addressed.

Team principal Andrea Stella said in Monaco that McLaren had felt “the downsides of being a customer team for the first time this season.” He added that the issue was not about lower priority from Mercedes HPP, but that customer teams have “less opportunities to integrate, to stay on the same timeline when it comes to addressing reliability problems or exploitation of the power unit from a performance point of view.”

The timing made the call more striking. Norris ended Friday fastest in Barcelona, 0.009 seconds clear of George Russell, with Piastri another 0.057 seconds back in third, giving McLaren clear reason to protect a potentially strong qualifying position. By spending a second curfew waiver this early, the team has now used half of its allowance for the season, but judged that the risk of another failure on a competitive weekend was the bigger threat.