2005 Chrysler Pacifica Severe Leak Near Passenger Tire Only Occurs Car Off

I have a severe leak near the passenger tire the leak only occurs when the car is off and parked. I have taken it to 2 mechanics and they don't see the leak. I thought maybe the water pump but the car is not overheating. The heat works sometimes it will heat for awhile then it will start to blow cold air. Can someone tell me what the issue is? I do also need the transmission flushed.