I'm sorry I thought you knew what was involved in flushing the system. To do this, you break every connection and use a flushing solvent blowing it through each line, the evaporator and the condensor and blow it out THOROUGHLY with compressed air.

This flushing is necessary to remove all the oil that was used with the 134. Once everything is thoroughly flushed and the flushing solvent is THOROUGHLY removed, THEN you have an empty system so that the correct amount of oil can be put in the system.

BTW, flushing of the compressor is NEVER done with solvent. Invert the compressor and turn it by hand to get out as much oil as possible, then put an ounce or two mineral oil or a synthetic R12 compatible oil and turn again by hand to rinse that through. Once all oil is out of all components and lines, and your new evap is in place, connect everything, saving the R/D for last as described earlier.

This is alot of work to go through, I know, but to do this job right, you would even have to do it if you stay with 134, because you have no way of knowing how much oil is in the system.