What an F1 winner has heard about apparent Mercedes engine issues

Former F1 driver Johnny Herbert has revealed he has heard that Mercedes have faced teething issues with their new 2026 power unit.

After finishing second in the 2025 constructors' world championship, Mercedes have widely been tipped as the early favourites heading into the radical 2026 regulation shake-up that will see the introduction of sweeping power unit and aerodynamic changes in F1.

But according to three-time grand prix winner Herbert, Mercedes’ preparations for the new season have not gone completely smoothly, based on information he has been told.

"I've not heard anything from any teams as of yet, but I have heard issues with Mercedes when they've tried putting the power units in the back of their car and it didn't start,” Herbert told JeffBet.

“After rumours that Mercedes were in the strongest position for 2026, it doesn't seem to be the case. It’s generally been quiet from the factories, teams are putting their heads down and preparing as best as they can.

“I'm sure there will be a lot of little problems, as there always are when coming into a new year with a new car with new rules. There are a lot of unknowns. It's different when the car is being tested in a factory and when it's racing on track.”

Mercedes are believed to have found a loophole in the 2026 regulations that will enable their engines to operate with a higher-than-allowed compression ratio at racing temperatures, potentially giving them a crucial performance advantage over their rivals.

Russell backed for F1 title challenge

Despite sharing concerning whispers about Mercedes’ power unit, Herbert has backed George Russell to challenge for the world championship in 2026, providing he has the right car.

Russell claimed two victories in 2025 and was one of the standout drivers of the season as he finished fourth in the world championship standings, behind the McLaren pair and Red Bull’s Max Verstappen.

"George Russell will be very important in the resurgence of Mercedes. They want to be right at the very front again. George can improve by being pushed by Kimi Antonelli too,” Herbert said.

“Consistency is the main thing dividing their competitiveness at the moment, George is very consistent, whereas Antonelli is not. It's a good mix of experience and the young. It will benefit them both at the end of the day.

“George will be aware that Antonelli will improve and has Toto Wolff's backing, but I think with the right car, George can compete for the championship.”