I have an older refrigerator someone wanted me to convert to R134A. It will need a new compressor,(dryer etc). The unit is 15 years old. My question is, would there be any freon metering problems switching to R134A. Personally I think the unit is too old to invest a lot of time and money in. Thanks in advance.
Cars get retrofitted with R134a all the time. As long as the technician is EPA certified to handle the R12 and it gets reclaimed properly and not vented to the atmosphere it should be fine... How much is all this work going to cost? Sounds like hundreds (3-4 min.) and you're still going to be left with an older fridge, with less energy efficiency. I would say that if you take the money you would pay this person to convert your fridge and combine it with what you'd be saving in energy the first few years, with the cost of anticipated future repairs on the old fridge, you could get a pretty nice replacement for it.
Also, if the R12 is reclaimed, and the system is brought down to a vacuum, then the synthetic oil with the 134a is generally compatible with any leftover oil from the R12, which has already been evacuated.
Compressor replacement/Freon Change 
