3.0q a/c

B6 A4
#1

I recently had my refrigeration system recharged on my 2004 a4 3.0q (w/79,9XX mi) since it was no longer performing well- at that point I had also noticed that the compressor didn’t come on when I turned on the air conditioner.

A mechanic told me that the a/c doesn’t come on until the engine is at 2500 rpm or greater even though I had been able to turn on the a/c at idle before I started having problems.

I tested the at idle after the service- a/c did not work. Tested again while cruising and shifted into a gear so the engine was at about 3000 rpm and in fact the compressor came on and the a/c blew properly cold air. Coming to a stop and idling the engine at ~800 rpm did not turn off the a/c system.

I find this strange. Is the clutch on the compressor failing? I heard temp sensor somewhere, but can’t make the connection why it could be that.

Any help/feedback is very much appreciated.

#2

The a/c should turn on at idle, I have serviced many cars a/c systems

#3

have you ever had a slight vibration come through the steering wheel when the ac was on

#4

I am aware of this. Any idea what the problem could be?

#5

I feel a very slight vibration when the compressor comes on. It only comes on en the engine speed is above 2500 rpm or so…

#6

It does seem as if the clutch is sticking and requires more momentum to allow it to release.