Bottas takes precautionary fresh Mercedes F1 engine for Silverstone

Valtteri Bottas will use a fresh Mercedes Formula 1 engine in Friday's first practice session at Silverstone while the power unit he used in France and Austria undergoes further checks

Although Bottas's retirement race from last weekend's Red Bull Ring race was due to a hydraulic issue, the team had some concerns after he stopped suddenly and parked on track that heat soak issues may have caused the engine some problems.

There were similar worries about Lewis Hamilton's car, after the world champion was halted by a fuel pressure problem, but his power unit has been passed fit.

But Bottas has been given a new V6, turbo, MGU-H and MGU-K for Silverstone. Each part is the last he can use before penalties kick in.

After being checked over at Mercedes' Brixworth engine base, the Austrian Grand Prix engine will be run on track on Friday at Hockenheim before being returned to the pool for further use, assuming it is deemed to be healthy.

A team spokesman said: "It's a precautionary measure as PU2 suffered high temps from heat soak after retirement in Austria so might carry some risk.

"He [Bottas] is taking a fresh one here then we will run the other one again in Hockenheim to check it properly."

Technical director James Allison noted earlier this week that stopping a car on track always carries some risks for the power unit.

He explained: "Every time the car stops in an uncontrolled way, where a failure happens and the system is then shut down in a manner that is unusual, and the car can suffer all manner of unknown gremlins, we can't be completely sure until we've done all the necessary checks to be certain that the bits of the car that are sealed, and which do attract sporting penalties, weren't in any way affected by these uncontrolled shutdowns."