I changed the entire A/C system (to be compatible with R134) in 2013. It had cost me about $1200. This year, the cooling is gone bad and I thought I needed a recharging. My nearby gas station filled up the gas, changed the valve and now has confirmed that I needed a new compressor plus drier.
My car has 160000 miles.
My car has an automatic transmission.
Unfortunately it is not unheard of for R134 converted vehicles to go through compressors more frequently. R134 requires higher running pressures than R12 did. Two things to make sure of this time around for longer compressor life.
Make sure they put the correct amount of refrigerant oil in the system.
Make certain they used a compressor that has been built/rebuilt to handle the higher pressures required by R134.
If you’d like a second opinion on this, consider YourMechanic, as a certified technician can diagnose the issue with your A/C and help you fix it accordingly.