Hyundai Repair: Squealing noise, hyundai elantra ve, hyundai elantra

Question
Hi,Thank you very much for your comments.
I examined the alternator belt. It looks fine. At least
not that loose to make that sound. When I more carefully investigated the problem, I found that the squealing noise
is coming from under the Engine plastic cover, from the leftmost side of the engine, which is the closes side to
the drive belt and alternator belt. The noise does not
exist when the car is cold. But in the first minutes, when
I drive it a bit, the noise starts. This noise gets more noticeable when I slow down.
Thank you
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The text above is a follow-up to ...
Hyundai Elantra 2000
-----Question-----
Hi, I have a Hyundai Elantra VE 2000. I hear a squealing noise from the area around the Engine. The noise starts when I rev the engine, even if it is in neutral. I changed
all three drive belts (where cracked), but the noise is still there! The timing belt and water pump has been changed 4000kms before (just 6 months ago!). Any idea?
-----Answer-----
If it sounds like a belt squeal, check your alternator belt to be sure it's tight enough.  This belt is especially prone to squealing.  In general, if you can flex the belt at all with a small amount of pressure, it's still too loose.  Even many professionals leave this belt too loose because it needs to be tightened significantly more than most drive belts.

Answer
I'll presume you're referring to the timing belt cover since there's not much under the rocker cover that would make a squealing noise.

Under the timing covers is a tensioner pulley and an idler pulley for the timing belt.  It's possible the bearings in one of these pulleys are failing.  

Before going through a lot of disassembly, it may be a good idea to try to narrow the source of the noise using a long screwdriver as a probe.  Simply touch something (nothing that's moving, such as a drive belt or the power steering pump pulley) with the end of the screwdriver and put your ear on the handle.  The noise will tend to be loudest when you touch the object that's making the noise.