Does it have hydraulic tappets? If so the engine may sound "clattery" for a few seconds as the oil is pumped up to the tappets. If it goes quite after that then there's nothing to worry about.
Does it have hydraulic tappets? If so the engine may sound "clattery" for a few seconds as the oil is pumped up to the tappets. If it goes quite after that then there's nothing to worry about.