It could mean the beginning of the end for your belt or the idler pulley, have them both checked out.
No, check idle pulleys and belt tensioner.
If you have replaced the belt, tensioner and idler pulleys, then the problem could be the water pump bearing, alternator bearing, camshaft bearings, power steering pump or any of the items attached to the serpentine belt. You may try to isolate the sound by listening with a length of rubber hose and place it near the areas where the 'noise' you hear may be emanating from. Just be careful not to get the hose too close to the engine fan or belts as it can get caught and cause damage or injury.
Pulley noise can be an indication of a component needing replacement. Pulleys contain wheel bearings which can and will wear out increasing noise. However, noise around the pulley can also mean other rotational components have a problem. Such conditions cannot be guessed and need professional-experienced mechanical diagnosis.
the KUIPER BELT
If you look under the hood on the passenger side near the belt, there is a diagram near the belt location.
near the equator
Near the equator
Whining noise near belts had pulleys adjusted any idea what is causing this
If a lighted splint is put near of a mouth of a test tube containing hydrogen gas squeaky pop sound is heard.
Pluto's orbit is near the beginning of the Kuiper belt.
noise and pollution
take a lighted splint (match) and place beside the test tube. If a squeaky pop sound is made then it is hydrogen