Renault insists it has enough spares for 2015's remaining Formula 1 races, despite Red Bull suggesting it could run out of engines after a troubled Italian Grand Prix.
Daniel Ricciardo and Daniil Kvyat both took multiple engine-change penalties at Monza as Renault sacrificed the Italian race to try to build up a pool of useable power units for the rest of the season.
But the situation was further compromised when a newly-fitted engine failed in Ricciardo's car in Saturday morning practice, necessitating a further swap onto a seventh unit.
Ricciardo reckoned that had created a dire situation for Renault.
"We're short on engines. There are literally no others available," he said afterwards.
"I think we've got two now, but if one more goes I think they've got to start building some more in the factory."
But a Renault spokesperson told AUTOSPORT the company is certain it has sufficient spares "to cope with any situation" and that running out of engines was inconceivable.
The Monza failure was caused by a problem with a non-Renault component in the car's airbox, and Renault is still unsure whether the engine can be reused.
Red Bull team boss Christian Horner summarised the squad's current engine availability as "one and a bit with Ricciardo, and two and a bit with Kvyat", clarifying that the 'bit' referred to remaining mileage on already-used power units.
SCEPTICISM OVER UPGRADE
Renault has yet to use any development tokens this season, and having exceeded its allocation of engines already, Red Bull will have to take further penalties to fit the upgraded power units when they arrive.
AUTOSPORT understands Renault is still attempting to have revised engines ready for the Russian GP next month, but a debut for the following race in America is more likely by the time all dyno work has been completed, with Red Bull not expecting anything until Austin.
Horner said Red Bull - which is splitting with Renault at the end of 2015 - would have to consider whether the upgrade justified penalties.
"It hasn't been confirmed to us how much it will be, or how much performance it will be either," he said of the revised engine.
"So when we understand what the performance gain is you have to weigh up whether it's worth taking a penalty.
"We'll wait to hear from Renault on that."
Ricciardo added that his expectations of the upgrades were limited.
"I wouldn't be too optimistic," he said.
"When we get it in the car, then I'll start to ask more questions.
"Until we get it, I'll keep quiet and keep driving it.
"Even last year we got a lot of hope that we'd get a bit more horsepower at this race or that race, and sure we got a bit more but it was never as much as we were told.
"Until I drive the car and feel more horsepower, I won't get too excited."