It is my understanding that most A/C systems will not engage the compressor if the refrigerant is below a certain level. Being that an 85 300D has a refrigerant capacity of 2.9 lbs., Is there any way the system could run and semi cool with only .40 lbs of freon in the system? I think I just got taken to the cleaners.....He said he added 2.5lbs of R12 to my system at $48.00/lb.

Just looking for comments....