While the new Mercedes W11 has emerged from winter testing as the car that many believe to be the fastest, it has not been an entirely smooth two weeks for the German car manufacturer.

It had to use two engines in the first test, after a power unit on Valtteri Bottas’s car failed following two days of running in week one.

That unit was then checked and given the all clear and put back in the car for the final day of this week’s test , after Hamilton suffered an oil system anomaly on Thursday afternoon.

Williams has also had to run three engines in testing so far, giving more reliability headaches to Mercedes as it finalises the specification it will take to Melbourne for the first race.

Motorsport.com understands that the engine issues that have hit Mercedes are not identical, so som

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