If you want to use R134a (why??) you need to purge the system of oil and replace it with R134a compatible oil. If you're going to Dura-Cool or
something like, the oil in the system is compatible. If the system is under pressure, simply add Dura-Cool to achieve proper cooling. The amount
will depend on how much original refrigerant is still in the system.
If the system is open to air, it must be purged and dried. First leak check and repair any leaks... popular places are lines and the compressor seal.
Then the action depends on available time and your pocket. Options are a) replace the receiver/dryer, drain the oil from the compressor and
condenser, and add 4 - 6 ounces of compressor mineral oil, pull the system down for an hour or so, and apply three cans of Dura-cool. If you're
cheeeep like me and have a pump on hand, pull a vacuum on it overnight, with a heat lamp aimed at the dryer. This will purge it of moisture. Then
charge with refrigerant. If the system is under pressure it should have enough oil in it.
--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased
