since yesterday, there has been a loud squealing from under the hood at idling. Could it be a bad alternator or bad belts? If it were loost belts, where would I have to tighten?

 

I have the same problem, so I would like to know this to, it's bugging the **** out of me... I think it's one of the belts, since there is not a lot of space on that side of the engine I'm afraid I'm going to have to pull the complete engine out to be able to reach it... I'm so sad...

 

Just tighten your belt.

1) Take front passenger side tire off.
2) Remove Plastic panel (the same one you remove to change your oil)
3) you will see the belt right in front of you. Twist it with your index finger and your thumb. You shouldn't easily be able to twist it more than 90 degrees.
4) If it's loose, look up - you will see the idler pulley. Use a 14mm hand wrench to losen the bolt on the pulley. (Don't remove it - just loosen it)
5) stand up, look under the hood and you will see the idler adjustment rod. Use a 14mm socket with extention to turn the idler adjustment rod clockwise.(tighten)
6) keep turning, periodically going back down under the car and checking until you reach 90 degree deflection.
7) tighten idler pulley bolt, put panel and tire back on
8) drive happily.

 

i checked the belts and they are tight. the squealing sounds almost like someone blowing a whistle and only happens around 6-700 rpm. anyone have any idea?

 

Just how tight are the belts? I believe the amount of deflection is somewhere between 1/4 and 1/2 inch when applying approx. 20lbs of pressure. If it's not the tension, perhaps it's the actual belt itself. There's several things that happen to belts.

1. They form cracks, which eventually lead to broken belts.
2. They stretch over time, which means they'll need to be tightened again at some point.
3. They form a glaze, which, if thick enough, can cause slippage (not the belt slipping off, but slipping on parts such as the idler wheel) - This could be the cause of your noise if the tension of your belts is correct.

You may simply need to replace a belt or two.

One thing I've used in the past is an old fish scale (the portable kind that you use to weigh fish) to apply a pretty accurate amount of pressure when measuring the amount of deflection. Getting just the right amount of tension is really important, since overtightening, though quieter, can be stressful on various components.

 

belts are actually in great condition in very good condition without glazing, but still no solution to the problem ;c

 

My idle pulley is messed up and it might squeel sometimes (1min during the morning warm up), belts are new and tightened. Pulley has some play in it, so it would prolly explain my squeeling.