Humming noise - engine compartment

[Ashmyster79]

Hi guys

Anyone had a humming noise from behind, probably behind the carpet in the engine pay. Sounds like a louder version of the aircon/fan. I know it's not that as it's switched off.

Would this be a water pump or belt? I have a replacement belt to put on but when I checked the old belt seemed ok.

Anyone had or got this type of noise?

It's not massively loud and I think but am not sure but gets a little louder if I steer to the left but this could be my ears playing tricks on me.

[san rensho]

Take off the serp belt and start the car, if the noise goes away, then its one of the accessories driven by the belt. Put the belt back on and using a piece of tube or a stethoscope, listen to all the accessories to identify the noise.

[Ashmyster79]

I read another thread and said something about the belt. I will do what you suggested with the belt off and see if it makes a hum sound. I need to put the new belt on really.

Thanks for the reply

[kk2002s]

If it's at start up and goes away after a couple minutes - Secondary Air Pump
If it happens after engine is real warm then it could be the Engine compartment fan that helps circulate air
These both are fan like sounds

If its constant then I +1 on a drive component off of the belt