I have a 2003 Citroen c5 which I bought last year, the A/c system has been empty for refrigerant since before I bought it. I have purchased the necessary equipment to vacuum, and recharge the system. in the manual, it says that the system takes 135ml of compressor oil. I assume most of this is still in the compressor. how much oil should be added when adding refrigerant? I am also changing the receiver drier.


You should evacuate the system, then establish a depression on it and leave it to find any leaks.

If there are no leaks then the manufacturer will state the amount of refrigerant and oil to be added.

You stated in your question that it requires 135ml, so remove any oil still in the system then add that amount.

The systems used by both my garages (one in UK, the other in CH) will control all parameters, oil, refrigerant and test accordingly.

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  • i was planning to put a vacuum on it and let it sit for 30 minutes or so to see if it keeps the vacuum. if there isn't any leaks is it then neccessary to add compressor oil when recharging ? – Kristian27 Jun 21 at 14:28
  • removing all the oil would mean I have to remove the compressor to drain and fill it.. that seems a little unnecessary if you ask me. – Kristian27 Jun 21 at 16:59
  • When the vacuum is pulled the oil vaporises so it gets extracted, well that is what happens with the proper gear as used by both my garages, and the system reports the volumes of refrigerant and oil removed. So when I last had my system checked and tested I received a printout if the amounts removed and the amounts refilled - paid for any extra needed to bring it up to spec. So since you say you bought the proper gear you should be ok. – Solar Mike Jun 21 at 17:15
  • i am pretty sure the oil in the compressor won't evaporate just by pulling a vacuum on the high and low side, som might get pulled out that is in the hoses but the majority will still be in the compressor, at least that is my understanding. I have read around a bit and think that only a small amount lost in refrigerant should be added. – Kristian27 Jun 21 at 17:31

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