Mercedes admit they're stumped by new F1 car problem suffered by Lewis Hamilton

Mercedes have admitted they still have no idea why Lewis Hamilton 's engine failed during last weekend's Australian Grand Prix.

Hamilton's race ended after just 17 laps of the Albert Park Circuit, forced to pull over when his power unit gave out. It was a miserable weekend for the team in general, as George Russell 's crash meant they left Melbourne empty-handed.

That result confirmed the Silver Arrows' worst start to an F1 season since 2012. And they could desperately do without any long-term engine reliability concerns compounding the performance problems they already have with their W15 car.

But, in a new debrief video released by the team, technical director James Allison admitted they have yet to get to the bottom of what went wrong. "The power units will return to the safe hands of the guys at Brixworth, who will be able to figure out what let go," he said.

"All we know is the symptoms at the time, which was a rapid loss of oil pressure followed by a shutdown of the engine to protect it because when you know you've got catastrophic loss like that, the best thing you can do for the future is kill it there and then.

"And then you have not just got like a load of molten metal. You have normally got a fairly clear evidence chain of what caused it. And then that lets you work better for the future.

"So, we do not know yet, Brixworth and High Performance Powertrains will do in short order. And no doubt as soon as we know then they will jump in with their characteristic energy to make sure that any risk that happens on any other engine is mitigated as best we can."

Reliability issues have been rare for Mercedes and Hamilton specifically - the seven-time F1 champion has retired just twice with engine trouble since 2018. And Allison insisted they do not expect the issue to be a recurring one that will have a great effect on how their season pans out.

He added: "We have drivers who are particularly good at keeping it on the island and our reliability overall is a strong point. It is unusual to have a double DNF like that. It is certainly not something we expect to punctuate our season.

"What we are more focused on is the pace because if you get the pace sorted out the season will be okay whatever happens. The baseline reliability of the car, our procedural approach to it and the skill of our drivers will tend to keep you clear of DNFs. All our focus is on the pace knowing that those other foundations are in decent shape."