Car rattles slightly on first start, but doesn't after the engine is warm.

Hello, There are a couple of different reasons this is heard on your vehicle: -A heat shield could be loose causing a rattle until warm -The variable valve timing actuator could be draining oil when sitting over night -The hydraulic valve lifters could be failing -Timing chain tensioner may be failing If you are under 100k miles, the dealer should cover all of these conditions since they are part of the powertrain. If not, you will need noise diagnosis completed in order to identify the source.