My car squeals when I have the air conditioner on. on 2002 Toyota Echo

Everytime I turn the air on and I am coming to a stop, my car makes a loud squeal. When I accelerate it gets worse, and then goes away. Sometimes I can rev my engine to get it to stop too. The only thing that doesn't really make sense is that the noise sometimes happenes when the air is off and I am starting my car. ALSO sometimes my car won't start at all, it acts like it is going to start, and the cuts off. Usually if I hold my foot on the gas pedle when starting it, it will turn over... but this usually takes several tries.... PLEASE HELP.

by in Greenwood, IN on October 12, 2009
6 answers
ANSWER by on October 12, 2009
I am leaning toward a stretched/bad serpentine belt, or the serp belt tensioner.
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ANSWER by on January 19, 2010
How do i fix it
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ANSWER by on February 26, 2010
Our 2003 Echo had a very similar (if not the same) problem. Loud squealing sound that would only stop at high rpm's, but always returned when idling. Very annoying. At the time, I suspected the serpentine belt being too loose as others have suggested. But in the end it turned out to be a failed component (the water pump) whose bearings were going out that was attached to the serpentine belt. Our car was coming right up on a little over 100,000 miles at the time. If you're at a similar mileage point, I would suggest having your water pump looked at.
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ANSWER by on July 12, 2010
You just need to tighten the drive belt, its very easy to do yourself (3 bolts around the alternator must be loosened - then you stick a pry bar between the engine and alternator and pry it back while a friend/spouse tightens the bolt and you are done, noise will go away. If the belt is old, you might as well replace it since it only costs $10 - the procedure is exactly the same.
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ANSWER by on June 17, 2011
It may be the a/c clutch. When you first turn on the a/c the clutch fails to start up immediately and the belt squeals in protest.. After the clutch starts to turn the noise will probably stop. If that is what is happening, you are in for a rather expensive repair. Take it to an a/c specialists and have them check it out.
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ANSWER by on August 23, 2013
My Toyota Echo does this too, it may be because I put in Xeon light bulbs that draw much more power. Since when my headlights are on and I turn on the A/C I have the same sqeals. I found changing the EFI relay fuse fixes it. You can get this EFI relay fuse anyplace. I just bought it at ADVANCED for 13 dollars. It you buy from a Toyota dealer it may be $50.