McLaren reaches key milestone as MCL40 is fired up for first time

With a deep breath from team principal Andrea Stella, McLaren fired up the MCL40’s Mercedes for the first time at its Woking factory, releasing a video of the moment on social media.

In 2023, McLaren confirmed it would continue running Mercedes power units into F1’s all-new 2026 engine formula, securing a long-term deal that extends to 2030.

McLaren MCL40 comes to life

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Running Mercedes power last season, the Woking team not only clinched the Constructors’ Championship, as it did in 2024, but added the Drivers’ title with Lando Norris taking the crown by two points ahead of Max Verstappen.

It’s a double that McLaren hopes to repeat this season.

McLaren has now become the latest Mercedes-powered team to fire up the 2026 power unit, marking the moment on social media as the team released a short clip of the monumental occasion.

You’re going to want your volume turned up for this 🔊🆙 pic.twitter.com/T31PAxIQsy

— McLaren Mastercard Formula 1 Team 🧡 (@McLarenF1) January 19, 2026

But ahead of a massive regulatory reset, McLaren CEO Zak Brown accepts McLaren with its Mercedes engine may be the title holder, but that counts for nothing this season.

“The reigning Champions label counts for little when we are all faced with a regulatory reset,” said Brown.

“The new regulatory era in Formula 1 will bring new challenges as the competitive landscape evolves, but our aim is to build on the foundations that brought us success in 2024 and 2025 and maintain the high standards required to compete at the front.”

“No one can possibly predict at this stage how the field will shape up in the opening races, but Andrea and his leadership team have been quietly working hard in the background for a long time now to give us the strongest possible chance to get off to a strong start.”

Mercedes is being widely tipped to lead the way with this year’s all-new power units as the team could benefit from 2014 lessons that saw the Mercedes power unit gain a march on its rivals. Mercedes claimed seven doubles on the trot, before adding an eighth Constructors’ title to the run in 2021.

Mercedes High Performance Powertrains Managing Director Hywel Thomas told the Beyond the Grid podcast: “Always possible. Definitely always possible.

“Although the regulation set was put together in a way to try to avoid that.

“So there are some constraints on there that do constrain you to certain ways of doing things. So if that’s gone well, it’s less likely that someone’s going to steal a march.

“But who’s to say someone hasn’t found a loophole, hasn’t found the amazing thing that nobody else has?”

Mercedes is reportedly one of two manufacturers that may have found a loophole in the wording of Article C.5.4.3. of the 2026 Technical Regulations.

It states that “no cylinder of the engine may have a geometric compression ratio higher than 16.0” and that the “procedure to measure this value will be detailed by each PU Manufacturer and executed at ambient temperature.”

However, it’s being reported that the wording has resulted in two of the power unit manufacturers, reportedly Mercedes and Red Bull Powertrains interpreting this as ensuring the compression ratio has to be met only in ambient conditions, but could otherwise run at a higher ratio when on track, potentially resulting in slightly higher power output.

McLaren and its rival Mercedes-powered team will get their first indication as to whether the Mercedes power unit could be the one to beat when testing begins in late January.

Formula 1 will host the first group test with the new cars beginning January 26th in a behind-closed-doors outing in Spain.

Teams will then head to Bahrain for the first open test with media and fans able to see the cars in action. That runs from 11 to 13 February with a second Bahrain outing from 18 to 20 February.

The F1 2026 season will begin with the Australian Grand Prix on March 8.

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