Moaning/turbine noise when A/C is on
 

Hello guys-

Haven't been around for a while.

I have a problem when my AJ16 XJS warm up, only with the AC on there is a moaning/turbine noise coming from the engine. The A/C cools fine and the compressor is not really very old. If I turn the A/C the noise will immediately stop. Once the car is warmed up the noise can happen while accelerating or at idle.

Any thought on this?

Thanks!!

Spike
Since nobody else has replied, a few questions:
Does the whining note change with the revs?
Does it cease if you turn off the aircon?
If, when the cold is blowing well and stably (eg you have asked for the lowest temp on the knob and it has been blowing cold for a while) you then increase the temp on the knob to good and hot, does the whining stop even though the aircon is switched on?


This last test is to see if the whining stops when the compressor stops compressing, as under these circumstances the compressor should stop for a minute or two as the unit's cold chamber will be down to its required temperature.


If, like my car, the radiator aux fan comes on with the engagement of the compressor, the fan starting and stopping tells you when the compressor is running and not running. The aircon unit just asks the compressor to maintain a given temp in the cold side air chamber, and switches the compressor on and off according to that parameter only.
Greg