Analysis of Lewis Hamilton's engine failure in Malaysia has shown that his Mercedes engine suffered a big-end bearing failure following a loss of oil pressure.
The failure struck without warning while Hamilton was leading the race and forced him to retire at the side of the track with 16 laps remaining. The engine was returned to Mercedes' engine base in Brixworth where more detailed analysis is taking place.
"Our analysis has shown that Lewis' engine suffered a big-end bearing failure," a Mercedes spokesperson said in Japan. "This happened without warning after 618 km and was preceded by a loss of oil pressure in Turn 15."
Hamilton will revert to the engine he used in Singapore this weekend, but still has one fresh engine left in reserve for the rest of the season. As a result of the failure, Mercedes will enforce new running parameters across all its engines this weekend, which will include a more conservative oil specification.
New power units were due to be fitted to the Force Indias, Williams and Pascal Wehrlein's Manor this weekend -- in line with the original plan for the season -- but they will now be delayed until Mercedes is satisfied it has learned everything it can from Hamilton's failed engine.
All five drivers will continue with the power unit they used at the last round in Malaysia -- as will Rosberg, who has had the latest specification of Mercedes power unit in his car since the Belgian Grand Prix.