Air conditioning sounds like turbine

Hi, on the last sat. (where it was so hot) I get into my A6 and what happens? I get only cold air blown in the face. Briefly read out the error memory with the codes for the climate and the result -> Coolant deficiency in the compressor. On Monday then to the friendly. Spare parts ordered and installed on the di. My A6 is 01/99 and has now 78000 km. Apart from that it is already embarrassing if the compressor after 5 years or a nevertheless quite low Leistu ng is already in the ass no the thing is still expensive. I still have this Audi CAR guarantee but the only thing that is guaranteed is that you always have to pay what yourself. fortunately I have to pay now only 220€ instead of 1030€. After all, the climate is now cold again. But since the new compressor is in it, my car sounds like an airplane turbine. You can hear my car when I’m at the entrance to the village and it’s not the stero system you hear. ́The sound is even but forever Is it now considered normal? Has one of you experienced it? Mfg Stephan