squealing noise

[chickster]

99/ Explorer LTD. 4.0 L when I turn on the A/C a loud squealing noise comes from the engine area. Also tried the heater and the same thing happens. Shut them off the noise stops. Only had vehicle 4 wks. new alt. installed just before I bought it.

thanks to all in advance

[wrigley123]

I could be the serpentine belt, or the A/C compressor going bad!

Mike

[rickthejeepguru]

that alternator could also be the problem check to see if it was remanufactured. the bearings in the alternators can go out and you will hear it under a load (an electrical load) that fan for your heater and your a/c draws a lot of amperage. the belt on the alternator could also be to tight (putting more pressure on the alternator bearings. if its a remanufactured alternator they could have gotten into production with bad bearings. if you really want to tell you need to pop your hood and turn your a/c or heater on and listen for the noise. try pinpointing the noise with either a stethoscope (availible at autozone for about $5 or a long screwdriver held to your ear (the handle side) and the bussiness end on the part you think the noise is coming from. this should pinpoint the problem