I have a 2005 NA. Recently I had my ac clutch go out so I ordered and replaced the compressor, expansion valve and the condensor.. The ac work fine after I flushed the lines, vaccumed out the systen and recharged it. However, a few weeks later the new compressor blew its seal. (SOUNDED LIKE A GUN SHOT) Thinking that I had puechased a bad unit, I ordered another from someone else.. I again installed the new compressor and evacuated the system again. After charging the system back to factory settings the ac worked while the car was idling in the drive.. Once I got it on the road, the new ac, which has a high pressure relief valve, blew the valve and I lost pressure on it again. I took the car to several mechanics, one whe even specialized on ac's and they can't figure out why the pressure keeps building when drivibg the car. The Benz dealer claimwd they did not have the tools yo even diagnose it. The only thing that I have noticed recently is the cooling fan is NOT going to high when the ac engages.. When it did work properly, it sounded like a small plane was about to take off from under my hood...

I need help please... No one around is familar with the car and like me, is just guessing as to what the problem might be....

Sweating in Arizona, Dale...