I was thinking the EXACT same thing. I thought the procedure was awfully weak for being the official factory dogma. Basically the mineral oil remains, same as the McParts-style 'retrofit' kits, and you just add PAG/POE oil on top of it... then wait a few years for the infamous Black Death to pooferate the system.
Back on soapbox... if you have an R-12 system, don't ever put PAG/POE oil in it! Use a mineral-oil compatible refrigerant only (R-12, AutoFrost, Duracool, etc). =) -- Dave M. Boise, ID 1994 E500 - 94kmi (Q-ship) 1987 300D - 258kmi (Sportline) > "Dave M." wrote: > > > > In case anyone wants to read the full official R-134a > > conversion/retrofit procedure from Mercedes, here's a link to the > > factory document (200kb PDF file): > > > > http://www.w124performance.com/docs/mb/other/134a_retrofit.pdf > > > > I'm reading the factory procedure for the old York and Harrison compressors > you listed above and thinking "what a crock". They attempt to remove the > mineral oil by flushing it with your old R12 and pulling a vacuum, put the > R134 adapters on, fill with R134+PAG, and that's it. No barrier hoses, > no mention of what happens to PAG when you run it through chlorine coated > condensor&evaporator. They get points for saying to replace the > receiver/dryer, > where most of the mineral oil is probably sitting.
