George Russell was forced to replace his power unit just before the Hungarian Grand Prix after a crack in the engine caused a coolant leak during qualifying. The incident occurred at the end of Q3 when the Mercedes team detected a sudden drop in water pressure, prompting engineers to pull the car off the track. As a result, Russell will be using his fourth power unit of the 2026 season, but because the replacement is of the same specification and does not exceed the four‑engine limit, he will avoid any grid‑penalty. He qualified a modest seventh, but a three‑place grid drop for a speed‑limit infringement handed him a sixth‑place start ahead of his teammate Kimi Antonelli.
The leak appears to have been triggered when Russell ran over the exit kerb at Turn 4 on his final flying lap in Q3. Mercedes officials believe the impact cracked a part of the cooling system, allowing a substantial amount of water to escape.
"We lost water pressure and I had a water leak. When I stopped on track, the car was leaking a load of water," Russell told Sky Sports F1, adding that he hoped the problem would not affect his race performance. He is currently 50 points behind championship leader Antonelli, and the team is eager to have the new unit up and running without further complications. This episode adds to a growing list of reliability concerns for Mercedes this season.
Both Russell and Antonelli have suffered points‑losses due to engine‑related retirements, and Russell was left "lost for words" after the previous round in Belgium when a software bug in the power unit curtailed his straight‑line speed and led to a race‑ending collision with Lewis Hamilton at Spa‑Francorchamps. Mercedes technical director Simone Resta confirmed that the software issue has been resolved for the Hungarian weekend, noting that the bug affected all cars but hit Russell harder because his unit was older and more worn than Antonelli's fresher package. Resta explained, "The software is the same for all the cars, and it was there in every car, but it affected George more than Kimi.
We also need to bear in mind that, when comparing their performance in the last few races, Kimi was on a fresher power unit, which is, of course, always a bit better than quite a used power unit. That will change in the next races when we start to have a fresher power unit on George's side. So, there's a bit of everything.
There's a bit of software, but there's also Kimi being out of phase with George's programme. You sum up everything when you look at the final result." Despite the setback, Russell remains optimistic about his chances on Sunday.
He acknowledged that his pace in the Hungarian session lagged behind Antonelli's, a trend that has persisted throughout the European swing of the calendar. "We were probably even further on Friday but we had the strongest race pace, which tends to say it's not a car problem but a tyre problem," he said, suggesting that the issue may lie more with tyre management than with the machinery itself.
Looking ahead to race day, Russell admitted that finding the right balance between qualifying and race setups will be crucial. "Time will tell in the race if we struck the right balance between the qualifying setup and race setup.
We probably know we could make the car faster in qualifying trim at the expense of race performance. It's going to be difficult to overtake.
It would have been nice to be higher up," he added. The Hungarian Grand Prix schedule is packed with support races, including an F3 feature race at 7:35 am, the Porsche Supercup at 9:05 am, and an F2 feature race at 10:20 am. The main Formula 1 action kicks off with build‑up coverage at 12:30 pm, followed by the Grand Prix itself at 2:00 pm on Sky Sports F1 and Sky Sports Main Event.
Viewers can also stream the event via NOW without a long‑term contract. In the broader championship picture, the current top‑ten qualifying order for Hungary reads: 1) Lando Norris (McLaren), 2) Charles Leclerc (Ferrari), 3) Oscar Piastri (McLaren), 4) Max Verstappen (Red Bull), 5) Lewis Hamilton (Ferrari), 6) George Russell (Mercedes), 7) Kimi Antonelli (Mercedes), 8) Isack Hadjar (Red Bull), 9) Arvid Lindblad (Racing Bulls), 10) Nico Hulkenberg (Audi). While Russell hopes to claw back some of the 50‑point deficit to Antonelli, he acknowledges that overtaking at the Hungaroring is notoriously challenging, and a strong race strategy will be essential to limit the damage.
Overall, the situation underscores Mercedes' ongoing battle with power‑unit reliability and the fine margins that separate success from disappointment in modern Formula 1. The team will be watching closely to ensure the new unit performs flawlessly, hoping that the coolant leak is a one‑off incident rather than a symptom of deeper mechanical issues.
If Russell can convert his sixth‑place start into a solid points finish, it could provide a much‑needed boost to his championship campaign and demonstrate that the team can overcome the technical hurdles that have plagued them this season.