Get a bottle with the gauge on it at advance or where ever you go. Turn the car on, put a/c to max, let it run for a few secs, connect the hose with the gauge and R-134A to the spout in the pic (take the black cap off it obviously) and see where your level is at. You want it to be in the blue range, depending on which brand bottle you buy. Cost is like $20-30 for the stuff. If it is low and after you start filling it, it leaks out, you can check for the leak with a uv/black light and we sell an r134a additive to help you find where its seeping out of.