When I turn on AC, I hear high pitch noise from the vent, similar to brake worn out warning sound. when turn off AC but with fan still running, noise went away. In either case, no cold air comes out from any vents, only room temperature air comes out.
I checked from engine bay that I do hear AC clutch engaging and cooling fan working, you think that is the famous cooling/heat actuator problem? I heard that my car has three? What do you think? I have AC pressure gauge, OBDII scanner, I can check those if you need me to.
My car has 74500 miles.
My car has an automatic transmission.
Hello and thank you for contacting YourMechanic. The noise you are hearing is the serpentine belt burning on the A/C clutch pulley from the A/C compressor being locked up.
Open the hood and with a flashlight look at the A/C compressor and watch what it does when you have someone turn on the A/C switch. If the compressor does not turn and you see the pulley stop turning, then the compressor has seized. If the A/C clutch is working and the pulley turns the compressor, then the bearings inside the compressor could be failing causing the sound.
For the air at the vent being not cold, then the A/C system is low on refrigerant or has too much refrigerant. Also, if the FOT (fixed orifice tube) is plugged, then the air will be not cold.
If you'd like to have your A/C system diagnosed, then seek out a technician, such as one from YourMechanic, who can assist you with your vehicle at your home or office.
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