In Friday and Saturday practice at the Red Bull Ring, the problems were back.
"No, unfortunately not," said team boss Toto Wolff, when asked by the Austrian broadcaster ORF on Saturday if the Canada problems were fully resolved.
"We still have aches and pains that we have not resolved but we need to for the race. It's much like the cooling issues in Montreal.
"The sword of Damocles is hanging over us," admitted Wolff. "It's not dramatic, but it's costing us performance. We need to resolve it."
On Saturday morning, it is believed Mercedes' troubles contributed to Valtteri Bottas setting the fastest time in the final practice session before qualifying, even though Wolff said the Mercedes-powered Williams is simply "fast" in Austria.