AC Compressor Always Spinning

[Oliver sharp]

Help would be extremely helpful
so since I bought the car I have heard a clicking noise coming from the engine bay when driving, I decided to try find out what this was and it sounds like its coming from the ac compressor. however, the ac compressor spins all the time, I'm talking about the inside plate and ive heard it should only spin when the ac is on?
it spins with the ac turned off and also when econ is on, always spins and from what I have read this is wrong and it should only spin when on. ive tried turning it by hand with engine off and it does not turn or move.
can I clarify it is ment to be not moving and also does anyone know the next step about rectifying this, I think the clicking noise is coming from the compressor
would be so greatful for any help

 

[RAF_S7]

Hi Oliver,

Its difficult to diagnose without seeing it, but if you look at any modern AC compressor, the pulley that the belt is around will always spin, regardless of AC on or off. There is an electronic clutch mechanism that engages or disengages the actual compressor from the pulley depending on whether your AC is on or off. You can't see this in a lot of modern compressors just by looking at it.

Mentioning what car you have may help others offer advice....

There are a lot of things that click when an engine is running, from fuel pumps to injectors....

 

[Oliver sharp]

Sorry I forgot to put what car,
Audi A3 2004 2.0 tdi 3 door 140bhp, I've been told I should be able to see it stop when the ac is off the inside part is this incorrect information?

 

[Oliver sharp]

Believe it's this type, has a curved thing on the end

 

[rum4mo]

If that compressor is a variable displacement one, then it will be connected to the pulley at all times, and it will be running at a very low displacement mode if not required to pump refrigerant around the system. This is just a suggestion as I don't know which type of compressor Audi or VW used at that period in time. (a late replay I know!)