I have a 2008 Focus 1.8 diesel. Recently noticed a ticking sound from the engine compartment. The ticking sound increases with RPM.
I've had the bonnet up, and the noise is loudest towards the top of the engine on the passenger side. There's no obvious pools/leaks of oil, and when I've had my hands around it I can feel a gas moving somewhere near to the hose on right side of engine, although it's definitely not that.