You have a 1999 Saturn sl2 four door you need now how much ac compressor oil to put in the system and what kind on get for it?

You shouldn't try to add AC compressor oil yourself unless you're experienced with automotive AC repair. Adding the wrong amount or type of oil can severely damage your system. The amount of oil needed depends on the size of your system and how much refrigerant was lost. It's almost always added during a complete AC system evacuation and recharge, not as a separate step.

Instead of trying to add oil yourself, take your Saturn SL2 to a qualified automotive AC technician. They have the proper equipment to evacuate the system, determine the correct amount of oil needed (based on the refrigerant type and amount used), and add the correct type of PAG oil (polyalkylene glycol) for your system. Using the wrong type of oil will damage your compressor.

Trying to guess the oil amount and type risks causing significant damage to your AC system, potentially costing you much more in repairs than a professional service would.