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Re: E21 A/C R12--> R134a conversion (archive)
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Posted by Jim Baron on April 10, 2000 at 20:27:02:

In Reply to: E21 A/C R12--> R134a conversion posted by david on April 10, 2000 at 16:29:37:

: Hi everyone...
: At home i have the part CD from BMW and i checked for A/C parts on both european & american models of E21.
: Since USA aborted R12 for R134a much earlier than Europe, i wondered if BMW USA made special parts for R134a only. But BMW France couldn't get me the information... so maybe a dealer in the USA would know it, or perhaps BMW USA would know something...
: The only thing i was told for sure is that any late compressor (after 8.79) would accept both R12 and R134a. The part # is : 64.52.1.367.374
: I checked for the other parts that would need some changing to achieve the conversion and came to a very strange conclusion : some parts exist in the USA only, and i have the strange feeling that they are made for R134a... Why would they built new parts with a new part # to do the same old job as another part.
: euro part numbers :
: compressor : post 8.79 : 64.52.1.367.374 (same as US model)
: drying container : post 8.79 : 64.53.1.368.908 (i think this is an old ref for R12 dryer)
: drying container : post 8.79 : 64.53.1.371.590 (i think this would be a new ref for R12 dryer)
: expansion valve : 64.51.1.354.379
: filling valve on hose : 64.53.1.356.549

: USA models : often the same part number + another one that always has a 466 in it... which i think would be for R134a..; but never got the confirmation...
: compressor : post 8.79 : 64.52.1.367.374 (same as Euro model)
: drying container : post 8.79 : 64.53.1.368.908 (i think this is an old ref for R12 dryer)
: drying container : post 8.79 : 64.53.1.360.148 (i think this would be a new ref for R12 dryer)
: drying container : 64.53.1.466.299 (i think this would be for R134a)
: expansion valve : 64.51.1.354.379 (same as Euro model - R12 only)
: expansion valve : 64.51.1.466.020 (i think it would be for R134a)
: filling valve on hose : 64.53.1.356.549 (same as Euro model - R12 only)
: filling valve on hose : 64.53.1.466.289 (i think this would be for R134a)
: Why would BMW make a special valve to fill the A/C system if this was not to connect an R134a system that has different connections. And what a surprise, the part number also starts with XX.XX.X.466.XXX !!!

: For those who can manage to enquire about this strange thing, it would be great telling everyone if you find anything.
: By the way, the conversion ratio from R12 to R134a is 0.8 the quantity of R12 that the system was built for.
: For example if you car was made to take 1000g of R12, you will only fill 800g of R134a.
: Same ratio for USA measurements... i am just not used to ounces and pounds...
: And the oil in the compressor and whoel system needs to be changed for a specific oil as well as every O-ring.
: Good luck, and please keep me informed if you discover that all those XX.XX.X.466.XXX parts are made for R134a.

I don't know this as word from the factory, but I suspect that some of those parts differences have to do with the USA climate being, on average, a lot hotter and more humid than Europe north of the Alps -- requiring, therefore, higher capacity AC units and car radiators.

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