300-400ml of oil, but it is easy to add more to it, just use ordinary car 0W15 engine oil. In any case if you are recycling a modern compressor you will want to change the oil in it in any case, as the modern units do not use a mineral oil for lubrication, but use a POE oil, which reacts with moisture in the air to form a corrosive mix that quickly destroys the inner components. Used because the modern refrigerants are not compatible with mineral oils, so they use an oil that will pump around the circuit with the refrigerant and which will not make immiscible blobs at the low points. Change it out with mineral oil and it will last a long time. Simply use a cheap air system separator and muffler on the outlet and you can recover the oil or at least see how much you are losing out.