I know that sounds weird, but it is true. I had a very slow leak in the system... The A/C would work great for a month or so and then slowly not get cold, so I knew i had a leak somewhere. It took me a couple of recharges with dye to determine where the leak was. I saw nothing on the exterior of the car so I decided to swab inside the condensation tube with a tiny cloth affixed to a piece of stiff wire. I got instant results, whereas the guy at the Prius shop told me it could take a year for dye to show up inside the tube. I replaced the evaporator core along with 4 O-rings... Pulling the entire dash apart, etc... a big job! I did not replace the expansion device. The old Evaporators unit was filled with crud so I am surprised the A/C worked so well previously. So now that i went to the trouble of replacing the Evaporator core, and vacuuming the system out and filling with 16 OZ of 134a, I notice the temperature at the vent is only about 62 degrees.... why would that be? A/C Experts?
