However, you should NOT attempt to add refrigerant yourself. A/C systems are complex and require specialized tools and knowledge to charge properly. Improper charging can damage the system and lead to costly repairs.
It's best to take your 1998 Oldsmobile Intrigue to a qualified automotive technician or A/C specialist for any refrigerant-related service. They'll have the necessary equipment to diagnose the problem, evacuate the old refrigerant (which is crucial for environmental reasons and system health), and properly recharge the system with the correct amount and type of refrigerant.