The air conditioning system works. Cools to 0.4 degrees C (I think that is about 33 degrees F) but when the car is idling an intermittent squeak can be heard. It is reasonably loud and when you put your hands on the pipes running to the AC unit by reaching under the dash, you can feel the pipes vibrating. I have had the system checked and no one "down under"can seem to explain what the cause might be. Any ideas your way??