Dealer told me not to buy the AC R 134 retrofit Orings or valves or Compressor when i went to pick them up today. Said Shop Mechanics told him not to bother because R134 will blow up '83 AC System/ other mechanic standing there said he just basically stuffed the R134 in without a retrofit and 6 hours later, the system suddenly kicked in and nearly froze him. Another guy said just pull a vacuum, blow the Freon 12system out, thats all he does. Mechanics are very intelligent, Mercedes pros in a class next to Doctors. but the next time I get surgery I am going to get 12 opinions.

I hear you! If yudo a search, you will probably find a lot written on this BB concerning AC and the pros and cons of R134. Larry Bible from Texas provides a very good summary in my opinion.

Some things to consider, R134 is cheaper, but is not as efficient. Adding it to a system designrd (sized) for R12, will have a performance penalty, but you will only begin to notice it when your AC is running truly raunnib at max capacity. If you need an ice cold car on the hottest of days, you may not be satified.

R134 is not compatible with the seals and oil used with R12, so a complete rework is required. Do not just dump it in, that doctor, I mean mechanic, was a quack!

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Deezel
87 300TDT
150,000 miles

I have had much experience with this issue. You can only change over when: The compressor and the hoses are changed as new. I have seen the old hoses used and they are not barrier hoses. They will absorb some or all of the oil and the compressor will die. If you do not flush properly, you will have an acid corrosion problem (I don't know why, I'm not a chemist), but I have seen it before many times.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM