What cause your engine to squeal when turning on the ac?

the ac compressor has an electric clutch mounted on it , the outside of it the one the belt touches turns with the fan belt and everything else when ever the engine is running , the inside part the one that drives the shaft of the compressor moves only when it receives the electric signal from the dash switch for ac to run (there are a few other switches in the same pathway that could prevent it from receiving power too ) if your fan belt skids or squeals with engine running turn off your defrost/ac switch if it goes away then your ac compressor is most likely bad , if belt just continues to squeal then your belt and/or tensioner needs replaced

50k isn't new but also isn't that high a milage , how old is the belt ,as age as well as mileage are the factors when replacing belts , chalk dust or french chalk , which are the same thing , thrown onto the belt just as starting should stop the squeal , the squeal is caused by the inner side of belt that runs around the pulleys becomes shiney and cant grip as well as it used to

Your AC compressor on the engine is the likely problem, either the pump is frozen up or the front bearing is frozen up, don't run the system or the belt will burn and fly off and strands you. Get this taken care of right away before winter. Have a local shop listen to the noise to confirm my guess as to the cause.

Hi this sounds weird does the smoke come out from the front engine covers? the squealing could be the cambelt trying to turn a semi or completly ceased waterpump which would cause the smoke after a while, also without the waterpump working properly the engine will leak water and anti freeze out the overflow and overheat really quickly

Are you certain that it's the clutch assembly?
Check the idler pulley. Poor tension in the idler pulley spring will cause the belt to squeal AT THE ALTERNATOR, and it may sound like it's coming from the AC.
The AC pulley typically "freewheels" when the AC is not on and the engine is running.
Have someone turn the AC on and off while the engine is running and watch the operation of the AC clutch. If it's working properly, the clutch should "click" and the back part of the pulley should start turning or try to turn.
If the squealing noise continues when the clutch is freewheeling, it's probably the idler pulley. If the AC Pulley won't start freewheeling, it's probably the clutch.
To remove the clutch system,

• disengage the idler pulley and remove the serpentine belt from one of the pulleys.
• rent, purchase or borrow a puller from a local auto parts retailer (Auto Zone and O'Reilly auto parts are both helpful)
• some of the clutch systems have retaining bolts, some are just pressed in, figure out what you have before removing the clutch assembly using the puller.
• The puller is also designed to help put the NEW clutch assembly back on the shaft.

The idler pulley assembly is a lot easier to replace.

sounds like a/c compressor starting to fail. hope this helps.

Belt is loose and stretch a little caused squeal, need readjust to tighten it up.

sounds like the belt needs tightening or replacing so yes you are indeed correct about the squeal, as for the rumble depends on how bad the rumble is but it shouldnt be caused by either you mentioned.

yes...your engine belt is little bit lose that's y its causing noise...and hope when u speed up..it will stop squealing ..right?? so just tight your engine belt little bit and it will solve your problem in a min...take care n have a safe journey...n also if it help...rate it plz

HI, you can replace the bearings on this clutch and it will save you lots of money. the bearing are shot and dry.