.... right away I'll say that I'll be taking the car into the shop again for some other minor work, and I'll ask their A/C guy about this very topic, but I thought I'd ping you all as well.
Succinctly, how much noise does your A/C compressor make when engaged and how much engine drag do you notice?
Most of the cars I've driven over the years, and certainly over the last 10+ years have been large V8s where the impact of engaging the A/C compressor is essentially unnoticeable by the driver. You don't hear it running and you don't feel it. It is true that if the radio is off, and maybe the window is down while sitting still or one is hovering over the running engine with the hood up... you may hear the "click" of the clutch engage and some compressor noise, but that's about it.
However, on my 95 I did have some concerns where I suspect the compressor is too noisy and drags too much.
I did initially have an issue where I could clearly hear the "slap"(not just a click) of the A/C compressor clutch inside the cabin after I replaced the clutch. I have addressed that though, and that is no longer a problem. You can read about that in the following thread, but in summary it was too large an air gap.http://rivperformance.editboard.com/t6120-write-up-ac-compressor-clutch-replacement
When I picked up the Riviera about a month ago, the A/C clutch was essentially rusted up, and the system was very low on R134. After replacing the clutch I had my local mechanic evacuate and recharge the system. It is blowing cold now, not freezing, but cold. And the clutch/compressor seeems to be cycling at a normal rate.
When I take the car back to the shop for some other checkup work in a few weeks, he'll be rechecking the A/C system for leaks, etc.
But the issues I now am concerned about are:
1) When the A/C compressor is engaged, I can hear it running from inside the cabin as a low, not loud but still audible "groan"/hum. Interestingly I don't notice this as much outside the car or with the hood up, but just inside the car. That seems odd. I don't think I've ever been able to hear any "humm" from an A/C compressor, whether outside or certainly inside the car.
2) When the A/C compressor engages, it noticeably drags the engine. It isn't extreme, but you definitely know the compressor has cycled on. I've never been able to "feel" an A/C compressor kick in while driving a car. This seems abnormal? Note that this is a 95, and the compressor type and configuration is different than Series II cars. I know this is only a V6, but it is a large V6, and I've never felt an A/C compressor kick in on something like our Honda Pilot which is a 3+ liter V6. And yes, the car is automatically adjusting RPM when the compressor engages. RPM does not drop, but I can feel the drag as vibration through the pedals and a slight loss of torque as if you let off the gas just slightly.
Thoughts? Bad or dying compressor perhaps? Hope not, but if so, so be it.
Just looking for more info to share with the mechanic when it goes back in.