Mercedes has no concerns about Hamilton's Japanese GP F1 engine

Mercedes has dismissed worries about the state of Lewis Hamilton's Formula 1 engine, despite the world championship leader expressing concerns about a vibration after winning the Japanese Grand Prix.

Hamilton came on the radio following the chequered flag to say that he had experienced a vibration with his power unit in the latter stages of the Japanese Grand Prix and had been short shifting.

On a weekend when title rival Ferrari suffered more engine reliability problems, Hamilton's issue prompted suggestions that Mercedes could have hit trouble too.

But speaking after the race, Mercedes motorsport boss Toto Wolff said the telemetry indicated there was no problem.

"We didn't see anything on the engine," said Wolff. "We looked at all the metrics. We need to really understand what he meant.

"My assumption is that when you are in the lead, and your main competitor has DNF-ed, you hear things.

"The same applies for us in the pitwall or in the garage. You just want the race to finish."

Hamilton later suggested his radio message was more to his team to double check the engine, rather than because he was unduly concerned.

"I don't honestly think there's anything wrong with the engine," said Hamilton. "I just felt a couple of things so you just point out things that you might forget to tell them.

"You make lots of different switch changes and the turbos make strange noises and different vibrations come in, so I'm hoping there's nothing.

"I don't think there is anything, I think it was just low... short shifting which the engine doesn't like so much."

With Sebastian Vettel's race wrecked by a failed spark plug, it has emerged that Mercedes had to change a faulty spark plug on Hamilton's car after qualifying.