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....

How do you know you only have .40 lb of charge? This amount of refrigerant would not be sufficient to close low pressure switch unless there was a restriction in the system which increased the low side pressure. BTW who is selling r-12 for $48.00/lb. That's a really good price..

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Jeff L
1987 300e
1989 300e
1987 BMW 325

It may be too late to save you money on this recent job; I'd like to point out something that will save you money next time around.

BUY AND INSTALL YOUR OWN R12.

You can easily obtain a 609 certification at www.epatest.com or a number of other sites.
You pay about $20, read a 53 page book, answer 21 of 25 questions, and wahlah, you
receive a 609 card and certificate in the mail. I bought R12 recently..paid $18.00 for a can. Sams was and may still be selling 30lb. containers for approx $20 a lb. Professional mechanics buy it for this and maybe less. Knowing this, it makes me SICK when I read about people being charged 50-75 dollars a lb. for R12.

Mike Murrell
Boerne Texas
'91 300-SEL

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by jeffsr:
How do you know you only have .40 lb of charge? This amount of refrigerant would not be sufficient to close low pressure switch unless there was a restriction in the system which increased the low side pressure. BTW who is selling r-12 for $48.00/lb. That's a really good price..
<HR></BLOCKQUOTE>

I must have not made myself clear. My system was still producing cool air (barely)when I took it in. When I had the system serviced 13 months ago, the compressor would not engage and the system was only 1 lb down. This time, the compressor was engaged and the A/C guy said that he had to pump 2.5 lbs of R12 into the system (meaning there was .40 lb in the system before he pumped it up). I think he stuck it to me since I don't believe the compressor would still be engaging with only .40 lb of R12 in the system before I took it in.

Yep, you got hosed. If the compressor was cycling, there is no way you would need that much r-12 to get it up to snuff. BTW how is it working now. If it 's OK, then you really got hosed..

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Jeff L
1987 300e
1989 300e
1987 BMW 325

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by jeffsr:
Yep, you got hosed. If the compressor was cycling, there is no way you would need that much r-12 to get it up to snuff. BTW how is it working now. If it 's OK, then you really got hosed..
<HR></BLOCKQUOTE>

It's cooling a lot better, but it doesn't look like I'll get any satisfaction.... I called him on it but it was his word against mine.