* Find the leak: Simply adding refrigerant without finding and fixing a leak is a waste of money and harmful to the environment. The refrigerant will simply leak out again. A qualified mechanic can use leak detection equipment to find the problem.
* System pressure: Low refrigerant is only one reason for AC failure. There could be other issues like a malfunctioning compressor, condenser, evaporator, or expansion valve. Improper pressure can damage the system. A gauge set is necessary to check the system's pressure.
* Oil: Refrigerant contains oil that lubricates the compressor. If you've lost refrigerant, you've likely lost oil too. This needs to be replaced during a proper repair.
* Safety: Refrigerant handling requires specialized equipment and knowledge to avoid injury. The refrigerant itself is under high pressure and can be dangerous.
In short: While the refrigerant is R-134a, it's strongly recommended you take your 2005 Pontiac Grand Am to a qualified mechanic to diagnose and repair the AC system. Attempting to recharge it yourself without proper knowledge and equipment could lead to damage to the system, injury, or environmental harm.
