R 134A Retrofit Procedures
UPDATED BY TSB # 331226 DATED JANUARY, 1994Retrofitting an R-12 vehicle to R-134a requires careful preparation to insure that neither the vehicle nor the A/C service equipment has become contaminated.
1. When performed properly, the retrofit from R-12 to R-134a will have minimal effect on the system's performance in most climatic conditions found in the United States and Canada.
2. COMPRESSORS DO NOT NEED TO BE REPLACED AS PART OF THE NORMAL RETROFIT. An R-12 compressor that is operating properly can be left in the vehicle when it is retrofitted to R-134a. However, if a compressor failure is the reason the vehicle is in for service, and the vehicle should be retrofitted, OR if a vehicle has already been retrofitted with R-134a and the compressor fails at some time in the future, new compressors for use with R-134a are available. DO NOT use a replacement R-12 compressor for any R-12 vehicle.
On some vehicles with automatic A/C controls or low charge diagnostics, the A/C compressor may not engage if any diagnostic codes were set during the retrofit. Check to see if any codes were set in either the HVAC or Engine Control systems. If they were, clear the codes.
Refer to Technical Service Bulletins for R 134a Retrofit Procedures.