Adding AC coolant, or refrigerant, to your car is a straightforward task if your system is just low on charge. However, if there’s a significant leak, this is a temporary fix and professional repair is needed. For a simple top-up, you'll need a DIY recharge kit, which includes a can of refrigerant and a gauge. The most critical safety step is to confirm you are connecting to the low-pressure port. The high-pressure port can cause serious injury if mistaken.
First, start your car and turn the AC to the maximum cooling setting and highest fan speed. Locate the low-pressure port; it's usually on the larger aluminum tubing of the AC system and often has a black or blue cap labeled with an "L". Connect the hose from the recharge kit according to the instructions. The gauge will show the current pressure. Ideal pressure is typically between 25-45 psi, but this is highly dependent on the ambient air temperature.
| Ambient Air Temperature (°F) | Target Low-Pressure Gauge Reading (psi) |
|---|
| 65°F | 25-35 psi |
| 70°F | 30-40 psi |
| 75°F | 35-45 psi |
| 80°F | 40-50 psi |
| 85°F | 45-55 psi |
Squeeze the trigger on the can to release the refrigerant, shaking the can occasionally as directed. Do not overfill, as this can damage the compressor. If the air from the vents isn't cold within a few minutes or the gauge doesn't change, you likely have a larger issue. This process is for minor maintenance; a system that loses charge quickly needs a professional to find and fix the leak.
