Scirocco Central

My GT TDI is making what can only be descirbed as a 'wishy washy' noise when idling. It is almost like breathing or a heartbeat and it has only started recently. I'm sorry for the abstract words but thats the easiest way of describing it. Does anybody have any clue what it could be?

Off the top of my head and without any knowledge of this engine, I would take a guess at a loose or split turbo hose.....