Why Honda’s F1 Power Unit Lasted Barely Five Laps in the Mexico GP

The high-altitude conditions at the Autodromo Hermanos Rodriguez proved catastrophic for Aston Martin and engine partner Honda during the Mexico Grand Prix weekend. In the lead-up to the event, Honda trackside general manager and chief engineer Shintaro Orihara had recognized the circuit as a very challenging track for the power unit, but the true extent of the technical breakdown resulted in an early double retirement for Fernando Alonso and Lance Stroll after only five laps of Sunday’s race.

High Altitude Triggers Severe ERS Cooling Failures

The weekend had started on a relatively promising note during free practice sessions. Fernando Alonso finished second practice just 0.769 seconds adrift of pacesetter Charles Leclerc, and the AMR26 chassis accumulated 144 laps across the three practice runs. However, operational gremlins began surfacing ahead of competitive running. While Honda addressed driveability and turbo lag issues between FP3 and qualifying, Alonso suffered abnormal signals on the water systems during Saturday’s session. Both Alonso and Stroll were eliminated in Q1, missing the Q2 advancement threshold by four tenths of a second.

Sunday’s Grand Prix unraveled almost immediately when both cars were retired inside the opening five laps. Explaining the terminal breakdown, Orihara broke down the systemic failures triggered by Mexico City’s thin atmosphere:

We knew that with the special high-altitude circumstance of Mexico City, we would face some additional challenges compared to other racetracks for the cooling, said Orihara.

However, we found that our ERS cooling circuit was under heavier stress than anticipated and this is why we had to stop the car in different sessions.

Despite completing a series of laps during the practice sessions, the issue occurred today and during qualifying yesterday.

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At each race this year, we need to learn for 2027, even the hard lessons. We have a lot of data that we can bring back to this circuit next year, including on the turbo lag, and we will work on the solutions.

Orihara also emphasized that without the MGU-H—which in prior engine formulas assisted the turbocharger to offset lag—the newer, simplified power units experienced acute turbo response problems in the thin Mexican air.

Underlying Pace Clouded by Recurring Reliability Woes

While Stroll provided brief remarks following the disappointing race, Alonso offered a clearer assessment of the AMR26’s fundamental characteristics and hardware restrictions. The car is very good, the Spaniard said. The problem is just, we cannot do more laps than a certain number, apparently, with the engine. Hopefully we learned a lesson and we come next year more prepared.

Data from Sunday suggested the Adrian Newey-designed machine harbored unrealized pace. Alonso’s fastest three individual sectors—recorded before he entered the pits on lap three—indicated sector times comparable to Williams driver Carlos Sainz, even while Alonso was running on full fuel. Aston Martin chief trackside officer Mike Krack noted that the venue had originally looked favorable for the car’s baseline qualities.

On Thursday, when we sat together, we said this is a track that has a lot of low-speed corners, Krack said. And if we get the driveability under control, that we can be competitive. For example, corners like the stadium section, [Turns] 4-5-6, low-speed stuff.

Managing Team Morale Amid Seventh Retirement for Alonso

The mechanical surrender in Mexico marked Alonso’s seventh retirement of the season, putting an enormous strain on team motivation. Krack addressed the ongoing challenge of maintaining team-wide focus amid persistent setbacks.

It’s difficult for everyone to keep the motivation high in such situations, and we are struggling all year already, Krack admitted. We had a very difficult start of the year, then the period when we introduced the upgrades and the ADUO, we [had] a bit better results. Now, we have more trouble in terms of reliability. In Texas, we had different issues with incidents. You know, it’s part of racing.

Krack added: The thing is, everybody tries his best, everybody is motivated to do better, and I have no doubt about the motivation. We don’t have to motivate them, it’s motivating them the highest possible.

For his part, Alonso was adamant that his commitment to the cockpit has not wavered despite the ongoing mechanical limitations. I’m doing my best every time, every lap I do, every morning I wake up, every preparation I do, every food I take – everything is focused on performing at my best behind the wheel, he said.

Why This Matters

The Mexico Grand Prix exposed a critical vulnerability in the integration between Aston Martin’s chassis and Honda’s modern power unit architecture, particularly in cooling capacity under thin-air atmospheric demands. With technical regulations eliminating components like the MGU-H, engine builders must rely on revised configurations that require careful thermal management. As Honda uses current track data to engineer durable solutions for 2027 and beyond, addressing these recurring reliability deficits remains urgent for Aston Martin to fully exploit the competitive pace designed by Adrian Newey.

Frequently Asked Questions

Why did Aston Martin retire both cars in the Mexico Grand Prix?
Both Fernando Alonso and Lance Stroll were forced to retire within the first five laps of the race due to severe overheating in the Honda power unit’s ERS cooling circuit, caused by the low-density air at Mexico City’s high altitude.

Why was turbo lag such a significant problem in Mexico?
According to Honda’s Shintaro Orihara, newer power units do not feature an MGU-H, which previously assisted in spooling up the turbocharger to reduce lag. In the high altitude and thin air of Autodromo Hermanos Rodriguez, managing turbo response without that system created notable driveability hurdles.

How many race retirements has Fernando Alonso recorded this season?
The DNF at the Mexico Grand Prix marked Alonso’s seventh retirement of the season, highlighting a persistent battle with reliability despite the AMR26 showing flashes of top-ten competitive pace.