Paddock rumblings in Montreal suggested that amid pressure from customers Red Bull and Toro Rosso, Renault was struggling to deliver a scheduled mid-season upgrade for its turbo V6.
However, it is now reported that Renault boss Cyril Abiteboul has revealed that the next major engine upgrade will in fact not be until 2018.
Asked about that, Toro Rosso driver Sainz said in Montreal: "We expect updates from Renault.
"We are not putting pressure on them, because we know that nothing good will come of that.
"We are partners, and we will wait as long as necessary. But I am sure they will find a way to increase the efficiency of the engine."
Both Toro Rosso drivers were forced to retire from yesterday's Canadian Grand Prix.