McLaren's poor start to the season hit another low after Stoffel Vandoorne suffered more engine problems and is set to be handed a grid penalty for Sunday's Russian Grand Prix.
McLaren endured a series of engine reliability setbacks at the Bahrain Grand Prix last time out and both drivers, the Belgian Vandoorne and two-time former world champion Fernando Alonso, were given replacement parts for this weekend in Sochi.
But more problems were identified on Vandoorne's car after Friday's first practice, which resulted in his McLaren being fitted with another new unit.
The fresh engine moves Vandoorne beyond the limit for engine parts because it is his fifth before the fourth race even starts.
He is expected to be penalised by 15 places on the grid, a sanction that has become almost commonplace for the team during its troubled relationship with engine suppliers Honda.