Here's the proper approach:
1. Diagnose the Problem: Low refrigerant is usually a symptom of a leak somewhere in the system. Before adding refrigerant, you *must* find and fix the leak. Otherwise, you'll just be wasting refrigerant. A qualified mechanic can do this. They'll use leak detection dye or electronic leak detectors.
2. Professional Service is Recommended: Recharging an AC system isn't a simple DIY job, especially for older cars. It requires specialized tools and knowledge to properly evacuate the old refrigerant (important for environmental reasons), vacuum the system to remove air and moisture, and then add the correct amount of refrigerant and oil.
3. If you *must* attempt it yourself (not recommended): This is risky and may lead to further damage. If you proceed, you will need the following:
* AC Refrigerant: The correct type and amount of refrigerant for your 1997 Pontiac Grand Am is crucial. Check your owner's manual or an online parts catalog for your car's specific refrigerant type (likely R-134a, but verify).
* AC Refrigerant Charging Kit: These kits are available at auto parts stores. They include gauges to monitor pressure, hoses, and a fitting to connect to your car's AC system.
* Vacuum Pump: Essential to remove air and moisture from the system before adding refrigerant. This is often included in higher-end charging kits.
* Safety Glasses and Gloves: Refrigerant is harmful if it comes into contact with skin or eyes.
Steps (Only attempt if you have experience and the correct tools):
1. Locate the Low-Side Service Port: This is usually a Schrader valve (looks like a tire valve) on the AC line, typically near the condenser.
2. Evacuate the System: Use the vacuum pump to draw a vacuum on the system for at least 30 minutes to remove air and moisture. The vacuum should hold (no pressure increase).
3. Add Refrigerant: Follow the instructions on your refrigerant can and charging kit. The gauges will help you add the correct amount of refrigerant. The ideal pressure will be indicated by the gauges and should match the specifications for your vehicle's climate and ambient temperature.
4. Check for Leaks: After recharging, observe the system for any leaks. Look for bubbling or frosting.
Again, professional service is strongly advised. Improperly charging your AC system can damage the compressor, leading to expensive repairs. The cost of a professional diagnosis and repair will likely be less than the cost of replacing a damaged compressor due to a DIY attempt.
