90 minutes before his first race for the Swiss team in Melbourne, mechanics went to prepare the grey C32 for the race but "fuel suddenly splashed out of the car," according to well-connected Blick correspondent Roger Benoit.
"(It was) a problem with the fuel tank, which is directly behind the driver."
Team manager Beat Zehnder: "It must be a crack in the tank. It's something I've not experienced in twenty years."
Benoit revealed that Hulkenberg's C32 - which could not be raced in Australia - has now been sent back to Switzerland, despite practice for the Malaysian grand prix looming in mere days.
He wrote that the 25-year-old will use the spare car at Sepang, while another spare is sent to Malaysia from Hinwil as soon as possible.
"I'm bitterly disappointed but at the same time I'm not blaming anyone," said German Hulkenberg on Sunday. "Things like this happen in racing."