Why Mercedes fear a DNF in future F1 races

Mercedes has expressed fears of an engine failure in the coming races as a reason for numerous engine changes in their factory and customer cars over the last two race weekends.

Speaking at the FIA press conference over the USGP weekend, Toto Wolff expressed his concerns about engine reliability. More recently, the team's chief strategist James Vowles has also touched on those concerns in their latest race debrief.

Mercedes driver Valtteri Bottas had to undergo an engine change at the Russian GP, followed by another at the USGP. Lewis Hamilton had an engine change at the Turkish Grand Prix at a critical point in his championship battle with Max Verstappen. The team's tone after the Turkish weekend did resonate with concerns about the reliability of their engines over a long season.

Mercedes express DNF concerns for remainder of season

Mercedes driver Valtteri Bottas during the 2021 USGP at Circuit of The Americas in Austin, Texas. (Photo by Mark Thompson/Getty Images)

Of the four drivers on the grid changing their power units over the USGP weekend, three were Mercedes-powered: Bottas, Sebastian Vettel (Aston Martin) and George Russell (Williams).

On being asked about the reliability issues during the press conference, Mercedes team boss Wolff said:

“I think you can see that we are suffering with reliability this year. We’re going onto the sixth engine – I believe it is for Valtteri – and it’s not something that we choose to do but, on the contrary, we’re trying to really get on top of the problems, and we haven’t understood fully.”

The Austrian explained the issue further, saying:

“I think we are a step closer now, so it’s not always that we are always, literally, easy with having the engines. We’re hanging on for dear life supplying all customers, and that is not trivial.”

Without getting into details about what the issue is with their engines, Wolff said:

“I wouldn’t want to disclose what it is, for obvious reasons, but it is always a concern. I think that, when you look at Monza, for example, Valtteri had to start from the back, and we’re losing points on the way.”

The Mercedes boss added:

“We are trying to push the performance every year, and this year, we’ve come to a point where that has cost us points. Over the last seven or eight years, that mindset has won us races and championships, so would have hoped to have less penalties and use less engines, but this year, it has really hit us hard.”

Post the Turkish GP, Wolff had mentioned that they were not discounting the possibility of Hamilton swapping another engine, despite the critical stage in the drivers’ championship. The reigning world champion is 12 points adrift of title leader Max Verstappen, and another engine penalty could make it difficult to close that gap over the next few races.

Mercedes GP Executive Director Toto Wolff talks during the Team Principals Press Conference ahead of the 2021 USGP in Austin, Texas. (Photo by Dan Istitene/Getty Images)

Reverberating a similar tone in Austin, the Mercedes Executive Director said:

“I can’t say whether we will be taking one and what the percentage is, but obviously, the risk is still there, and what is difficult to evaluate is do you want to pre-empt the situation and take another penalty and take the hit – or do you want to really run it and then possibly risk a DNF – and that is a discussion that is happening as we speak and we haven’t come to the right answers yet.”

Mercedes Chief Strategist Vowles explained the engine changes, saying:

“The reason is that we are balancing performance versus reliability to the end of the season. One failure to finish a race, be it because of a chassis or Power Unit fault, would be catastrophic for the championship and as a result of that, we are managing that in the best way possible to the end of the year.”

Explaining Bottas’ three penalties in four races, Vowles said:

“In the case of Valtteri, that meant taking one further ICE to make sure we had absolutely the best compromise. As to whether it improved [Bottas'] performance, yes, a small amount, but it's more about the balance across the remainder of the season rather than one event.”

Mercedes driver Bottas switched to his sixth ICE (Internal Combustion Engine) in Austin, while Hamilton is currently on his fifth. Vowles believes the engine change was necessary for future races, saying:

“So this change, as painful as it was during the Austin Grand Prix, will actually pay dividends across the next few races.”

While Red Bull Racing replaced Verstappen's fourth engine in Russia, the team insists it might not have to swap engines further into the season. As Mercedes attempts to resolve its engine issues, its championship could be under threat with five races remaining in the season.