Originally Posted by dmorrison

What year??

If it holds a charge for a couple of months, you have a leak. Where a sniffer, or dye will let you know.

The R12 to R134 conversion without flushing the oil out is not good. The R12 oil is not compatable with the R134 oil so neither will stay in suspension and do there job. eventually the compressor will fail due to lack of proper lubrication.

Do a search on R12 to R134 conversion. I did mine (correctly, I am licensed) and went back to R12 due to the lack of cooling with R134. Plenty of info and debate on the R12 to R134 conversion in the W123 body ( if your car is a W123).

Dave