PenelopePen

Can anyone tell me what this sound might be? I only hear it sometimes, when I do hear it I am usually either parked or driving slowly. Once car has had some time to warm up I no longer hear it and it doesn't happen all the time. My engine has also become louder (sometimes) upon cold start up. I have attached a video of the noise. I drive a 2011 Subaru Outback 2.5i limited. Link to engine noises: