Mercedes wary of losing Rosberg's F1 engine in British GP practice

The leak was discovered on Rosberg's car just before the afternoon session at Silverstone, and after sitting out the opening minutes Rosberg climbed into his car expecting to join the action.

But Mercedes eventually decided it could not be confident that its "quick fix" had done the job, so it decided against running at all.

Mercedes' executive director (technical) Paddy Lowe said: "It became clear shortly before FP2 began that there was a water leak on Nico's car.

"We were optimistic of a quick fix initially but, after further checks, we opted against running the risk of losing an engine from the pool.

"We will be looking into that overnight to understand what happened and our apologies to Nico for losing him some important running time this afternoon."

Rosberg spent FP2 following team-mate Lewis Hamilton's data and radio traffic in the Mercedes garage, and he believes the team had a strong enough day overall that he can make up for lost time on Saturday.

"I really felt good in the car this morning so I'm not too worried," he said.

"I will do my homework, and I was listening to what Lewis was doing, watching his data, trying to learn a few bits that I can take on for my car.

"I wasn't far off anyway this morning in terms of balance so it will be fine.

"Tomorrow we'll just pack some more things into FP3, maybe a short long run as well, and it will be OK."

MORE TO COME FROM HAMILTON

Hamilton topped both sessions on Friday, although he wasn't happy with his fastest lap in FP2.

"The car is feeling good but we've got some work to do on the balance," said the world champion.

"It's really difficult to pinpoint where the target is because corner to corner the wind is moving everywhere.

"In one corner you've got oversteer, in one you've got understeer, and in another it's balanced.

"It's difficult to know where you've got to change the car but we'll work hard to do it.

"Obviously we didn't get to see the pace Nico has, and I don't necessarily think my single lap was spectacular.

"I don't see [Rosberg's missed track time] being much of a problem for him."