No, you generally
cannot safely change an AC condenser in a 1987 Chevrolet van without discharging the refrigerant. While some minor work might be possible *before* disconnecting lines, the condenser is part of a sealed system containing refrigerant under high pressure. Disconnecting lines without properly recovering the refrigerant will release it into the atmosphere, which is illegal in most places (violating the Clean Air Act in the US) and harmful to the environment. Refrigerant also poses safety risks if it's inhaled or comes into contact with skin or eyes.
You must use a refrigerant recovery machine to safely evacuate the refrigerant from the system before disconnecting any lines. Otherwise, you risk significant environmental damage and potential injury. Improper handling of refrigerant can also damage the compressor.
