2000 Volkswagen Jetta Leaking

2000 Volkswagen Jetta 6 cyl Automatic 117000 miles

My coolant is leaking but I have no idea where its leaking from? I recently took to one mechanic and they said they ran a water test on the engine and they said it ran like it was the head gasket. I took it somewhere else for a second opinion and he believed it was leaking out from the top of the coolant tank but was drying before it could drip to the ground so he just replaced the coolant tank. He also said the car didn't drive or sound as though it was the head gasket. A month later i'm on my way to work and the coolant light goes on so I add more and its ok. A few days later on my way to work I noticed the hood had steam coming out from it so when I pull over the tank is almost empty and I can see the fluid dripping out but I don't know from where. I've heard plenty of suggestions from people on what it might be (head gasket, thermostat, hose leak) but my regular mechanic screwed me over so now I don't know if I should have it looked at or just get rid of it. One other note, it has never over heated whenever the coolant went low. I need some help please!