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.

[RamonToyota]

Thanks for the piece of tubing tip, it is a good one! I´ll see if I am able to identify the source.

No, it doesn't change with revving. Initially, I though it was related with air con.

Thank you so much for your help!

[APS]

I should have said as well that I've heard this noise on other, perfectly healthy – or at least that I have considered healthy – cars. Hence, it's unlikely a serious problem. Are you sure it has not been there before? 

[RamonToyota]

Thanks for your comments!

I have been checking old videos of my car I have in my phone, and I can say that I am sure it wasn't there in the past. Not sure if it is related to, but it started after servicing and re-gas the air con. After re-gas, I also noticed that the car started leaking water, and I assumed was normal when using air con.

Video of the leaking below: