Sounds like your serpentine belt, belts usually run for around 20 bucks. Locate your serpentine belt under your hood if the noise is comming from it when running go ahead and turn off your viechle, try pulling it if it's noticeably loose you probaly need a new belt tensioner as well and what you hear is the belt slipping by lack of tension but if it seems okay proceed with taking it off. Once off spin every pully individually and listen to see if it's a pully with barrings that went out that's causing the noise if all your pullies pass the test simply clean all the pullies dry of oil or ANY lubricant and replace the belt

Check the fan belt is not slipping. You can do the trick where you get a bar of soap and rub it on the sides / edge of the belt until it's covered. This will help it grip more. IF it stops the noise, or reduces it, then you have an incorrectly adjusted fan / alternator belt or it's worn to much.

If it's not the engine itself your fine it's just a belt most likely if it's not a belt and it's the motor you've got yourself a problem. Now since I don't have any idea how many miles are on this vehicle I'm ganna say it's a belt most common issue but il have it check out and if it is a belt you better pray it isn't the timing belt!!!!

It sounds as though the fan belt is slipping. You need to get it replaced, but don't worry it is not an expensive job.

Hi it could be so many things from a belt which needs to be adjusted to a new water pump or altenator bearing. so time to get it looked at.

I have a high pitched whirring noise coming from my x reg saxo. It is present both in gear and in neutral. It stops immediately when I turn the ignition off. It sometimes goes away and intact went away for a few week and has now come back. Any ideas?