My wife's citigo has developed a rather strange noise from the engine.

It is a continuous woooooooo noise and if you place your hand over the air intake of the airbox it stops.

Again if the little pipe from the airbox is removed and covered with your finger it stops.

 

My thoughts were that it was the PCV valve in the rocker cover but I have replaced this and the noise is still there ?

 

It definitely seems worse when the engine temperature is cold.

 

Has anyone else had this or is it possible it's something that we just haven't heard before ?

 

Thanks Simon

Anyone ??

Does it sound like its maybe a vibration resonating in a pipe that has been slightly loosened/tightened kinda like how sometimes if the water pressure drops a smidge in your house the flow starts vibrations the pipes and they hum?

 

 

Sorry for the delay in responding,

It's possible but why would it disappear when the intake is blocked off 😕

A pressure change in a hose can change it's stiffness, hence the way it resonates. Anything can change if you put your hand on it.

 

Is the noise more like a pure-ish tone (low pitched whistle) or buzzy (a mechanical resonance)?

 

Can you post a sound file or video - someone here may recognize it if they hear it!

The noise is more of a pure-ish sound .

I will try and upload a video later 

 

Thanks

Simon

Righty then,

Hopefully you can hear the constant whistle noise in the attached video clip

 

Hi, apologies for the zombie thread revival but this topic appears high in google and is exactly the issue I have with a 2013 Citigo. Wondered whether the author found what the fault was or meantime if anyone else has had this same issue. 
it's a constant wooooooooooooooooooooooo noise when running. I can't place the origin of it in the engine bay. 
As per the original post if you put finger over end of pipe that goes to rocker cover valve the noise goes. 
sometimes get a little chirp of the same noise after engine has shut off (around same as the throttle valve control motor does its little reset).

could just be me but when revving the engine the noise appears to drop off when the revs are dieing but comes back as idle engages again.  
Any help much appreciated.

@Fabiasi any chance you could post what the resolution was?