Squealing in Engine when not fully stopped or accelerating

[tut35711]

First off I'm somewhat of a novice when it comes to auto repair.

I have a 2001 Ford Explorer Sport with a 3 position switch inside for 4x4 high and low, 2x2 and O/D capabilities as well.

Problem presented a week ago. My engine squeals any time I am not accelerating. Starts out as a soft whine but seems to increase in intensity the longer it goes between stops or accelerations. As soon as I come to a complete stop or press the gas pedal, the squealing stops. The moment I let off either the gas or brake pedals it starts over.

Read on some other forums that it might be the belt and that grease would quieten the sound. Those sites also recommended trying WD-40 first to see if it quieted the noise. I tried using WD-40 to no avail.

Any clues would be greatly appreciated.

 

[Lefty2053]

Could be a bearing from something attached to the serpentine belt. Alternator,A/c Pump,Fan Etc. Using a long piece of pipe or something else you can listen to each part when it is making the noise. An assistant to rev the engine slightly to create the squeal.

 

[radman]

I had a belt tensioner that made some strange noises off an on. Check it for looses.
Mike

 

[DjDom]

Most of the squeals from an engine come from the belt and it's counterparts.

Check (and replace if you haven't yet) the serpentine belt in the engine.
The sound could also be coming from the idler pulley which is very common as well. The pulley does not drive anything and is just there to position the belt.
If that doesn't fix it, your belt tensioner may be doing it.

Those are the 3 most common things.
And by the way, adding WD-40 to your serpentine belt is a bad idea and will only make things worse. Never grease it..