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Q: AC only blowing out hot air

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I hear a rattling/squealing noise when I turn the AC on. It goes away as soon as I turn the AC off. I hear this sound as long as the AC is on, whether I am in drive, reverse, or idling. It seems to be coming form the pulleys, I am not sure if it is a problem with the compressor, tensioner, or the belt. At one point, it shut down the engine.

Generally a bad tensioner will make noise at all times when the engine is running. If the noise only happens when the AC is turned on then the compressor is at fault. The use of an engine stethoscope can help in determining the source of the noise. You may want to enlist the help of a mechanic, such as one from YourMechanic, to assist in this repair as they will have the equipment to evacuate the AC system, replace the compressor, and refill the cooling system to ensure the AC system is operating correctly.

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