Mercedes team boss Toto Wolff has not ruled out the possibility of a fifth engine change for Lewis Hamilton before the end of the season.
Hamilton took a 10-place grid penalty for the Turkish Grand Prix after he was fitted with his fourth Internal Combustion Engine (ICE) of the season.
F1 rules permit three per campaign, and after dropping to 11th for the start of the Turkish GP, Hamilton clawed his way back to fifth as rival Max Verstappen finished second to reclaim the championship lead.
Formula 1
'It's going to be exciting until the end' - Verstappen on title race after Austin win
Red Bull driver Verstappen is ahead of Hamilton by six points with six races remaining, and Wolff acknowledges his driver could face another penalty as the season reaches its climax.

Lewis Hamilton

Image credit: Getty Images

"It [fourth ICE] can last until the end of the season but there could be a moment where we say is it worth taking a fresh one because the other one is still at risk," Wolff told Sky Sports F1.
"So this is something that is going to be really a work in progress."
Mercedes favoured a grid penalty over the possibility of a DNF, while Hamilton’s teammate Valtteri Bottas – who won the Turkish GP on Sunday – has already had a fifth power unit installed.

ISTANBUL, TURKEY - OCTOBER 10: Race winner Valtteri Bottas of Finland and Mercedes GP celebrates in parc ferme during the F1 Grand Prix of Turkey at Intercity Istanbul Park on October 10, 2021 in Istanbul, Turkey. (Photo by Umit Bektas - Pool/Getty Images

Image credit: Getty Images

Wolff said the team had no choice but to change Hamilton’s engine, but hope it will not affect his chances of winning an outright record eighth title.
"We had to do it. We saw some data on the Internal Combustion unit that didn't look very promising and a DNF is a total killer for the championship.
"We've seen over the course of the season that we've had some little gremlins that we weren't completely sure where they came from and how much performance they could potentially cost.
"So we'd rather have a new engine in the pool and that we understand that can possibly go longer."
United States Grand Prix
'I gave it everything but couldn't convert it' - Hamilton laments Texas near miss
United States Grand Prix
Verstappen pips Hamilton to win United States Grand Prix