Booyah45828
Full Access Member
Blackdawg beat me to it, but if there isn't refrigerant in the system, the compressor clutch shouldn't engage and won't be turning the compressor innards. No need to remove the belt on an empty system.
Any time I add oil to a dry system, It's typically half in the compressor, half in the accumulator/receiver drier. The compressor is the only item that needs lubricated, so oil should definitely be added to it, but I've seen instances where people added the total system oil volume into the compressor and then destroyed it at first start because of slugging. They're not really made to pump liquids.
With r134a, a good long vacuum is necessary. I've gone an hour plus on humid days. It can take a while to boil out a system and you want zero water in there. Also make sure to use a good vacuum pump and you can suck down to within 1 inhg of your current barometer. If it can't do that, you have a bad pump or a leak that needs to be found.
Also, I've used variable orifice tubes with success, but they've always been with systems that were cleaned spotless.
Any time I add oil to a dry system, It's typically half in the compressor, half in the accumulator/receiver drier. The compressor is the only item that needs lubricated, so oil should definitely be added to it, but I've seen instances where people added the total system oil volume into the compressor and then destroyed it at first start because of slugging. They're not really made to pump liquids.
With r134a, a good long vacuum is necessary. I've gone an hour plus on humid days. It can take a while to boil out a system and you want zero water in there. Also make sure to use a good vacuum pump and you can suck down to within 1 inhg of your current barometer. If it can't do that, you have a bad pump or a leak that needs to be found.
Also, I've used variable orifice tubes with success, but they've always been with systems that were cleaned spotless.