Renault forced to replace three MGU-Hs after Ricciardo problem

Ricciardo lost most of Friday's second session to a technical problem that Renault Sport boss Cyril Abiteboul said was the result of an MGU-H change implemented "in a hurry".

Abiteboul explained an "extremely intensive" period since the French engine manufacturer's focus shifted to reliability in the two weeks following the Azerbaijan Grand Prix had put Renault on the limit in terms of reliability-testing the modification.

As Ricciardo's Red Bull team-mate Max Verstappen and Renault works driver Hulkenberg all had the same specification MGU-H fitted for the race at the Red Bull Ring, these have all been replaced.

The second works Renault of Jolyon Palmer and the Toro Rossos of Carlos Sainz Jr and Daniil Kvyat do not have the MGU-H specification that caused Ricciardo's problem, so they have not been changed.

"It meant a lot of changes to the technical definition, and sometimes when you work in a hurry you don't have time to do all what you are supposed to be doing in terms of sign-off," Abiteboul told Autosport.

"There was one particular decision made on the MGU-H where we hadn't had the time for it to be signed off.

"We tried something, it was really on the limit of introducing or not introducing that modification.

"Indeed it created an issue on one of the cars only, Ricciardo's, and that issue meant that we took the decision to change all the others.

"We tried something and we had the capacity to react overnight, and hopefully this will not repeat again."

Abiteboul explained that Renault would be able to solve the MGU-H problem at the factory because the original change related to "ancillary" parts and did not count as a fresh component under the FIA's engine regulations.

Drivers can only use four of each engine component over a season before incurring grid penalties and Ricciardo, Verstappen and Hulkenberg are now on their fourth MGU-H of the season.

If they use a fifth between now and the end of 2017 they will pick up a 10-place grid penalty.

Several other drivers are also close to receiving a grid drop.

Palmer took a fourth MGU-H yesterday, while Haas drivers Romain Grosjean and Kevin Magnussen are using their fourth Ferrari turbochargers this weekend and Ferrari's Sebastian Vettel moved onto his fourth turbocharger several races ago.