MONTREAL (AFP) - Lewis Hamilton's Mercedes team have postponed the planned introduction of a new upgraded engine at this weekend's (June 9/10) Canadian Grand Prix due to reliability concerns.
A team spokesman said the scheduled change of engines would be delayed by one race and that the new units would be used at the French Grand Prix later in June.
"We had hoped to introduce the PU2 this weekend," said the spokesman.
"But a quality issue means that his has now been delayed by one race.
"So all Mercedes-powered cars will be running PU1 again this weekend, too, before the new units are available in France."
Mercedes engines are used not only by the factory race team, but also by the Force India and Williams teams.
The delay is a blow to defending four-time champion Hamilton as he bids to claim a record-equalling seventh win at the Circuit Gilles Villeneuve and extend his lead in the drivers championship.
The Montreal circuit is a power-hungry track where engines can be decisive and rivals Ferrari are expected to introduce their scheduled engine upgrade for fellow four-time champion Sebastian Vettel.