It seemed like Mercedes were off to a dream start with their 2023 Formula 1 challenger after the team praised the car for being 'much calmer' compared to the troublesome W13.
But it seems those positives have masked a deeper problem the team has encountered with the W14, after what they described as a "challenging" second day of testing in Bahrain.
After just completing four laps into what would have been a race simulation, George Russell stopped out on track with a session-ending hydraulic failure that cost them valuable track time.
The team also struggled to get the car balanced across the changing track conditions according to Trackside Engineering Director, Andrew Shovlin.
"We've not had a strong second day; stopping on track with a reliability issue wasn't great and we have struggled to get the car balanced well across the changing conditions.
"We've got some investigations going on to understand why this has been such a challenge today when yesterday it was fairly straight forward."
Problems with the floor
It's been no secret that Mercedes has been encountering some problems when on track, notably with Lewis Hamilton who had several snaps of oversteer on corner exit.
The team downplayed the struggles by saying the car was outside of their setup window, but RacingNews365 Technical Analyst, Paolo Filisetti, noticed a deeper flaw that stems back from its predecessor.
"The Mercedes W14 seems to be just slightly better than its predecessor," said Filisetti.
"Huge dynamic problems are visible when they are negotiating the corners, with the rear end of the car behaving unpredictably.
"According to rumours circulating in the F1 paddock, the floor on the W14 seems to not provide a consistent aero load, resulting in it behaving differently across the ride height variations."
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Strange loss of downforce
Speaking to German media, Wolff claimed the car was suffering from a 'strange loss of downforce' at the front axle, which has yet to be identified.
The team boss hopes that a solution to the problem can be found overnight, but admitted to Auto Motor Und Sport: "We are a bit lost, as we don't know where we stand right now."
Shovlin also said the teams investigations will continue into the night to understand more ahead of the final day of testing.
He added: "That work will continue into the night and no doubt we'll understand more come the morning."
Indeed, Mercedes team personnel was spotted having an in-depth meeting in the paddock after the session including Wolff, the drivers and engineers.