I finally put in (i.e. the mechanic put in) a rebuilt ACcompressor in my 1985, 190 D (2.2 l). Oh, they also converted and flushed the system (and, yes, installed new receiver dryer). Guess what-it did not work. turned out that the factory assumed that SOMEBODY will know to replace the speed switch at the back of the compressor (Nippondenso 10P15C) from the old compressor to new one. Well, nobody did and the new compressor is now installed and the system is pressurized and it does not work. Both the garage and the re-builder claim that replacing the switch will release the entire refrigerant from the AC system. However, the switch does not appear to be designed to hold the pressure of the refrigerant. Moreover, when taking out the switch from the old compressor (after it was out of the car), I released a little bit of pressure behind it. It seems that whatever refrigerant was behind the switch, it was not connected to the rest of the AC system. So, the question is, do I have to have the system evacuated before replacing this (*^&%$# switch???
Thanx