Despite insisting from the start of the season that there was nothing wrong with them, Ferrari has been granted permission to make changes to their engine due to reliability issues.Ferrari replaced both engines prior to the race in Australia, and Alonso experienced an engine failure in Malaysia. Alonso is down to six engines for the rest of the season.
The linked Autosport article speculates that the issue lies in the area of the pneumatic valves used, which were thought to be leaking during use. If the valves don't open and close at the correct speed, it can lead to serious engine problems. James Allen's sources apparently claim that the issue has to do with how some of the moving parts in the lower-engine parts were fabricated.
It is unknown if the already used (but unbroken) engines can have this fix retroactively applied to them.
