When AC is switched on, grinding noise can be heard

2007 CHEVROLET OPTRA
196,000 MILES
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DANISHSIDDIQUI
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I own a Chevrolet Optra Manual 1.6 L. When I switch on the air conditioner, I can hear a grinding noise coming from somewhere in the engine. On pressing the clutch, I can feel the vibrations. Have got the throttle body replaced on the mechanic's suggestion, but it has not helped.
Jun 30, 2013 at 1:02 PM
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SEANGRANT00
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Hello,

Have you had any work done to you air conditioning?

This could be a couple things,
-Your A/C is overcharged
-Your compressor clutch is bad or about to fail
-Condinsation Drain (rare)
-If the noise is closer, blower motor or air door problem

Let me know

Sean
Jun 30, 2013 at 11:13 PM
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DANISHSIDDIQUI
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Hi Sean,

Thanks for your prompt reply.

I just bought this from a friend of mine. It's been over 2 months, but, this AC problem was there since the start. Earlier the car would always shut down the moment I would start the AC so I never noticed this noise. For now, the mechanic managed to set the RPM a bit high, so at least it doesn't shut down. However, there is this grinding sound which is a bit scary. I really don't know what to do with it, cos the garage guys are a piece of junk here.
Jul 1, 2013 at 3:26 AM
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SEANGRANT00
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This could be a couple things, how cold is the air coming out?

It could be a low amount of oil in the system, which is causing more friction. It also could be a bad clutch or compressor. The bearings in the compressor could also be going out. See if you can push on the clutch and see movement or play. This would indicate a bad bearing.

Sean
Jul 1, 2013 at 4:24 PM
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DANISHSIDDIQUI
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I can feel the grinding whenever I press the clutch. Looks like i'll have to get the bearings checked.
Jul 2, 2013 at 5:09 AM
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DANISHSIDDIQUI
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however, one thing confusing is why does RPM go down the moment AC is switched on?
Jul 2, 2013 at 10:21 AM
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SEANGRANT00
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Normally any addition of a load to the engine will bring the RPM's down. The computer typically raises the idle to balance this out. In your case, the bearings going out would put a higher load on the engine. When you get this fixed it should go back to normal.

Sean
Jul 2, 2013 at 1:58 PM
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DANISHSIDDIQUI
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great ill let you know
Jul 3, 2013 at 10:15 AM
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SEANGRANT00
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Sounds good

sean
Jul 8, 2013 at 12:11 PM