Mercedes have revealed that his third power unit failure of the year, 15 laps before the end of the race in which he held a 22.7s lead over the Red Bulls of Daniel Ricciardo and Max Verstappen, was due to crankshaft bearing failure.
Detailed forensic investigations conducted by Mercedes engine chief Andy Cowell and his team determined that a big-end bearing failure occurred without warning after a sudden drop in oil pressure as Hamilton negotiated Turn 15 to complete his 40th and final tour in the 56-lap race.
The engine was one of the units he ‘stockpiled’ by taking so many grid place penalties at the Belgian Grand Prix at Spa, where he fought through to finish third as team mate Nico Rosberg won from Ricciardo. Mercedes have confirmed that it had only 618 kilometres on it.
The failure will have repercussions for all of Mercedes’ runners this weekend.
Hamilton will have to fall back on the engine he raced in the Singapore Grand Prix, while Rosberg will retain the one which took him to third place in Malaysia.
Meanwhile, as a precaution their customer teams - Williams, Force India and Manor - will also continue to run their Malaysian power units, instead of implementing their scheduled switch to fresh ones, while Mercedes carry out further analysis of Hamilton’s broken engine.
Mercedes have also told them to run to revised running parameters as a precaution, one of which is a different oil specification.