1994 E320 station wagon model 124 a/c orifice filter, expansion valve issues

[dmorgan]

My 1994 Mercedes E320 station wagon model 124 a/c (air condition) compressor was blowing warm air. The mechanic did a recharge on the a/c compressor as a service. The a/c ran cold for three days, then the a/c blowed warm air again. I took it back to the mechanic and told him about it. He said I need a new a/c compressor and he does not do repair work on a/c compressor. So after several months went by, I went to another mechanic closer to my home area, and recharge the a/c and told me I need a/c compressor and a drier or accumulator. He said he can do the work on my mercedes. However, my experience with mechanics in the area where I live stay away from working on mercedes. So I ordered a rebuilt compressor and a dryer. When the package arrived, the dryer and a/c compressor looks the same as the ones were in the Mercedes. According to the instructions in the package, the a/c system uses an Orifice filter and it must be replaced. I cannot find or locate this particular orifice filter on my mercedes. In addition, the instructions also indicated if the system uses an Expansion valve and it must be clean or replace with new expansion valve. Again, I cannot locate this expansion valve on my mercedes. Then I did some research and it appears the orifice filter and expansion valve both are part of the a/c system. Any ideas as to clarify this issue? Your response is greatly appreciated.