You won't believe my wife's coolant problem

So my wife has this 2001 VW Passat.
Last year the car developed a coolant leak. We changed the coolant to the GM pinkish/orange kind (if memory serves correctly) and never turned on the AC again, since we felt the two were related - the leaking completely stopped for an entire year.
Fast forward to a couple weeks ago, when my wife turned the AC on during a terribly hot day, and the car starts to leak again. She picked up the green coolant for every make and model and has kept the AC off, but the car continued to leak. We started to fill it with the Dexcool that saved us in the past, but unlike last time the leaking continues.
What is the most likely cause of the problem? Is it possible there's still some green coolant in the mix causing the leak? or did the moment of weakness cause more serious damage to the system? The leak seems to be coming from the front of the car.