Anthony Davidson says Peugeot was surprised by the multiple failures its cars suffered in this year's Le Mans 24 Hours.
The factory 908s were dominating the event until one car dropped out with a suspension failure and the other two each retired with blown engines after or while leading.
Davidson's #1 car had run flat-out for half the race distance after losing four laps on Saturday evening with an electrical problem. But the #3 and #2 cars failed while being driven at a reserved pace in full control of the race.
"We were driving well and controlling things, well within ourselves," Davidson told AUTOSPORT. "We didn't see any engine failures at all until then, I've never seen one at Peugeot since I have been driving for them. Very, very rare. So for it to hit so hard was quite a surprise for everyone.
"You can't win this race even if you have one problem. You have to have a completely faultless car that is obviously fast enough. And that is exactly what our competitors had."
Davidson added that Peugeot believed it had done enough testing to have confidence in the reliability of the 908 prior to the event.
"Quite unbelievable," he said. "Don't get me wrong, you can consolidate, but we ran this very engine configuration of the car, that's why we spent so much time doing 30-hour tests - three times, to make damn sure the car doesn't break. And until now it hasn't broken, it had been bullet proof.
"To be honest, if someone told me before the race that even one of the cars would have an engine failure, I would have been blown away. Flabbergasted. Like I say, that just doesn't happen with these cars. But you live and learn."