McLaren arrives at Spa this weekend with the latest specification of Mercedes' power unit — and a fresh round of questions about whether it should be building an engine of its own.
The timing of the upgrade has become a talking point. According to The Race, McLaren only fitted the newest Mercedes spec at the Belgian Grand Prix, two races after the works Mercedes team ran it in Austria, and after customers Alpine and Williams had already used it at Silverstone. McLaren held off because it still had mileage left on existing units, having burned through components early in a season pockmarked by reliability trouble — including two separate battery failures that stopped Lando Norris and Oscar Piastri from starting March's Chinese Grand Prix.
That sequence — works team first, McLaren last — reignited a debate about customer status, and Guenther Steiner did not hold back. Asked whether McLaren should walk away from Mercedes and build its own engine, the former Haas boss was blunt.
"Absolutely. They are a car manufacturer; they should make their own engine," Steiner said.
He argued the grumbling about being a customer follows McLaren from one supplier to the next. "They had issues with Renault at the time. They had issues with Honda. It's always something," he said, before adding the line that framed the week: "At some stage, you need to be a grown-up, and they've got enough money."
Steiner pointed to rivals who took the plunge. "Red Bull went for it, and they are doing pretty good. Audi went for it. They are a car manufacturer, they don't want to buy a Ferrari engine," he said. He did not pretend it would be simple: "Expensive. And difficult. It isn't easy to make an engine, but I think the first hurdle is the money and then the people."
McLaren, for its part, has been careful not to blame the hardware. Team principal Andrea Stella framed the gap as one of execution rather than raw power, saying the squad has yet to unlock everything the Mercedes unit offers.
"We still seem to have a little bit of a deficit in extracting the most from the HPP power unit," Stella said, adding: "We have work to do to exploit the potential of the power unit — there's more that is available."
Inside the garage, expectations for the Spa upgrade are being kept deliberately low. McLaren's technical director of applied engineering, Neil Houldey, warned the new spec is no silver bullet.
"We're confident that this update will add a bit of performance to our car, but we are fully aware that after a difficult British Grand Prix, mainly in terms of pure performance, even this round won't be that easy, so we won't be expecting any big change in terms of competitiveness," Houldey said.
The two positions sit awkwardly together. Steiner sees a manufacturer with the budget and the badge to control its own destiny and no more excuses to lean on. McLaren sees a customer relationship that still has performance left to find, if only it can extract it. What both agree on is that, at Spa, the engine in the back of the car is once again the story.
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