Renault says it suspects a 'fuel leak from a breather' caused the dramatic fire that engulfed Kevin Magnussen's car in the pit lane during first free practice for the Malaysian Grand Prix.

The Dane was returning to the garage following an installation lap when the Renault appeared to 'puff' smoke coming into the pit lane. Worse was to follow though when the Renault began spewing fluid just behind the airbox and caught alight.

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Forcing Magnussen to eject from the car quickly, Renault mechanics quickly extinguished the flames but with the fluid still pouring from the top of the engine running down the side-pods for the next few minutes, it would continue to catch flame sporadically until it was drained.

Speaking to Sky Sports F1, Renault technical chief Nick Chester says investigations are ongoing but has an idea of what caused the issue.

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"We had a fuel leak from a breather. We were running the tank full and running some experimental parts for Mexico, so a different set-up to the other car. It looks like the tank has pressurised. We're looking at what happened."

With damage to the Renault both inside and outside the RS16, Chester admits it may be difficult to get Magnussen out for FP2.

"Everyone looks OK, which is the main thing, and we'll try and get the car out for FP2. There was quite a bit of dust around but everyone seems to be fine. We are going to try and get him out, obviously there's a fair bit of work to do but we're well on with it and we're going to try and get him out for as much of the session as we can."

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