Honda says its energy-recovery system’s cooling circuit faced greater loads than expected in Mexico. For Alonso, the frustration was having a car with encouraging pace and another weekend cut short before he could use it.
Aston Martin has a clearer explanation for its early double retirement in Mexico. Turning that explanation into reliable running is the next challenge.
Honda says the cooling circuit for its energy-recovery system, or ERS, came under greater strain than anticipated at the high-altitude circuit. The problems interrupted several sessions and ultimately ended both drivers’ races after five completed laps.
That adds detail to Aston Martin’s initial explanation of abnormal pressure levels in the power-unit systems. It also answers a question left open during the race: Alonso confirmed that the MGU-K problem that stopped him in qualifying had returned on Sunday.
What Honda says went wrong
Mexico’s altitude was a known cooling challenge. Honda had prepared for it, but the demands on the ERS cooling circuit still exceeded its expectations.
The ERS is the electrical side of the hybrid power unit. Its MGU-K recovers energy under braking and supplies electrical power to help drive the car.
Honda’s trackside general manager and chief engineer, Shintaro Orihara, said the unexpectedly high cooling loads were behind the need to stop the car in multiple sessions. Although Aston Martin completed running in practice, problems returned in qualifying and the race.
For Alonso, Sunday brought a repeat of the MGU-K issue. Stroll’s retirement had a protective purpose: he was instructed to stop to prevent damage to the battery.
Those are important distinctions. Both cars retired amid the same broader cooling difficulties, but the team has not described two identical component failures.
Alonso’s frustration goes beyond the result
Alonso’s disappointment was sharpened by the performance he felt was available.
His encouraging practice pace had suggested Mexico offered Aston Martin an opportunity. Instead, the weekend became another exercise in managing problems, with too little uninterrupted running to turn that promise into points.
After the race, Alonso described the repeated MGU-K trouble and acknowledged how difficult days like this make it to maintain motivation. He nevertheless committed to continuing the effort in Brazil.
That is the tension at the center of Aston Martin’s weekend. There was enough pace to encourage Alonso, but reliability prevented him from finding out what it could deliver over a race distance.
For the mechanics and engineers, the outcome was equally difficult. Stroll pointed to the long hours the team had worked throughout the weekend, only for both cars to be out almost immediately.
What comes next in Brazil?
Aston Martin has only a few days to assess the problems before the São Paulo Grand Prix.
The immediate task is to turn Honda’s diagnosis into a car that can complete its running reliably. Honda’s post-race explanation did not announce a completed fix or guarantee that the issues would be resolved for Brazil.
Orihara also placed Mexico’s lessons in the context of 2027 development. He said the weekend had provided useful information, including data relevant to improving turbo lag, the delay between a driver asking for power and the turbo delivering its response.
That longer-term work matters, but Alonso and Stroll still have races to contest this season.
Brazil offers another opportunity. Before Aston Martin can make much of its potential, it needs to give its drivers the laps to demonstrate it.
