Lewis Hamilton is to use the engine that prevented him posting a time in qualifying in China as a spare.

The Briton suffered a problem with the MGU-H on the unit during qualifying that could not be resolved during the session and consequently prevented him completing a timed lap.

This, on top of a five place grid penalty imposed when the team opted to change the gearbox on his car, saw him start from the very back of the grid.

"The unit in question arrived back at Brixworth in the early hours of Thursday morning of the week following the race and investigation into the failure has been on-going every minute since its return to the factory," revealed the team.

"The MGU-H has been stripped and the issue is suspected to be associated with the insulation. The turbocharger will be replaced in addition to the oil pumps, after debris was found in the oil system. With the repairs completed, this unit will remain in the driver pool and travel to Sochi as a spare."

This year, drivers are limited to five power units, with grid penalties incurred if they need to exceed their allocation.

"There was plenty going through my head after China, as you'd expect," admitted Hamilton, who went on to finish the race seventh, despite incurring significant damage to his car in a first lap incident.

"After all these years, experience has taught me to stay calm and keep pushing forwards when I get knocked back," he added.