03 Corolla 1.4 engine noise

[RamonToyota]

Hi guys, please have a listen to the noise present on a 2003 Corolla 1.4 Petrol manual. The noise happens all the time, it comes from the right rear and right side, so it may not be specifically the engine. The noise doesn't goes away at any point and it sound like a continuous "mmmm".

What do you think could be? and cheap or expensive repair that probably doesn't worth to do?

Thanks!

 

 

[APS]

Sounds like air humming through a breather pipe. Engine sounds mechanically good otherwise. 

You can use a piece of tubing (garden hose type diameter) to listen through and try to pin-point the source. 

Does it change note with revving?

You can also remove the aux belt to eliminate any of the rotating ancillaries as the source.