How do you know which port to put in refrigerant in a car?
it usually has a blue cap on the suction port.
You can find the low pressure port near the compressor under the car on the driver's side. you have to put your car on a lift to get to it. Once you put the car on a lift, take the plastic shields off and you will find the compressor. it's in a very tight spot. Why would Lincoln do this is, I will never know.
You don't. The 2000 Saturn refrigerant is not Freon R12 it contains R134a. Add it at the Low pressure port. You have a leak or it would not be necessary to add refrigerant. It is illegal to add refrigerant to a system with a leak without first repairing the leak. Take it to a professional and have the leak fixed.