My air conditioner makes a whining noise when I rev the engine to about 3000 rpm and up. The noise goes away with the air off or below 3000 rpm. Has anybody else had this noise. Turn the radio off and listen.

 

I had the same problem with my 96 civic AC. Ask them to check your vaccum lines and valve. I had air entrapment there and when I speed up, it makes like a whisling sound. Flushed the coolant didn't help. They needed to take out the valve and replace with new one. The air wouldn't get out even with flush.

Tatewaki