Mercedes has 'question marks' over Stroll’s F1 engine failure

The Mercedes Formula 1 team has been left with “some question marks” as to what caused Lance Stroll’s engine failure during the Canadian Grand Prix weekend.

Mercedes introduced its fist power unit upgrade of the season in Montreal, an update which was made available to both the works squad and customer teams Racing Point and Williams.

All six Mercedes-powered cars ran the latest ‘Phase 2’ engine from the start of track running on Friday, before Stroll suffered a failure at the start of final practice. Racing Point subsequently reverted back to his original power unit for qualifying and the race.

Mercedes boss Toto Wolff said the German manufacturer is yet to determine the cause of the reliability problem.

“With mature regulations you are not seeing huge gains anymore with the introduction of new engines - we are making these smaller steps and reliability fixes,” Wolff explained.

“We are not happy for Lance and for Racing Point, they missed a complete session with a brand new engine that went bust.

“So we need to understand what it was, which we don’t at the moment, so there remains some question marks over what happened.

“But overall, I’m happy that we introduced the fresh engine. Just take it from there and try to learn with every mile we have on this engine, learn and optimise them.”

Wolff dismissed suggestions Stroll’s issue could prompt Mercedes to turn down its engines during the race.

“I think it came as a surprise to us but we have been running those engines on the dynos and still believe what we have seen on the dynos counts,” he added.

“You can’t turn them down or run them differently because of fear of failure because that is very difficult to judge. So that will not change how we run the engine.”