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E21 A/C R12--> R134a conversion (archive)
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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.



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