Strange buzzing/hissing engine noise

I have a constant strange hissing / buzzing noise in the petrol M13A VVT engine. It appears to come from the front of the engine, and I might say from the area where the power steering pump is. The "pitch" of the sound remains the same whether the engine is idling or working hard, just the intensity increases slightly on higher throttle.

However, when I turn the wheels on the parking lot, the noise does not change, indicating that the pump itself is probably OK.

On the other hand, it is just the time to replace all engine driving belts (belts are factory fitment and the vehicle has traveled 90 000 km - that is the scheduled interval for replacement).


The mechanic told me that it might just be the belt(s) that are making the noise, or some of the pulleys. I will be known after the belt change has been performed.

I am wondering if it could perhaps be this thing from the BigJimny shop:
www.bigjimny.com/store/power-steering-te...er-bearing-m13a.html


Anyway, I attached the sound recording of the noise. The mobile phone has a noise cancellation technology, so it filtered all the engine sounds leaving just this anomaly sound (just like someone was using a stetoscope to listen).

Can anyone discern what could this be?


P.S.: I will also try to get a "normal" sound recording of the engine without this fancy noise cancellation later in the evening.

I forgot to upload the actual sound recording. Here it is.

The belt tensioner bearing is possible, I would say that sounds more like the aircon compressor. Possibly the magnetic clutch is stuck in?

Yeah I would tend to agree with you, the pitch is wrong for my experience of the idler bearing. Though it is definitely a bearing on something.

Try listening through a wooden stick like I have tried explaining in here before.
Use one long enough not to get your clothes or hairdo into the belts.
Very old trick this and works great to isolate sounds and locate problems.

Thank you both for the suggestions. If it is the AC compressor's belt clutch, should the pitch or intensity of the sound change when the compressor turns on?

Also, would it be wise to turn the engine ON with one of the two engine's driving belts removed (just to see if the sound will stop when for example the power steering pump is not being driven)?