I have a '97 stock Z28 (A4) with 137K on the clock. As this car is not my daily driver, it gets driven once a week or so at most. It still runs like a champ.....that is until I turn on the Air Conditioner. When I do so, there is immediately a loud chirping sound from under the hood. If I am on the freeway with the A/C on, this chirping subsides and the car runs fine. However, If I am idling (say sitting at a light) the chirping resumes and the volt (amp?) guage dips way down into the red causing the car to run horribly rough. If I turn off the A/C....problem solved. I have searched past threads and discovered cars with similar problems being fixed by replacing a number of things from alternator, serp. belt, idler pulley, and/or tensioner. Any new ideas on this? My serp. belt is new so what should I check first? Thanks in advance.

-HH

 

Could be a bad A/C unit.

 

The bearings on my AC compressor are shot and make a howling/screeching/chirping noise when the compressor turns on. When the compressor is not on, there is no noise.