Overheating problem my 2000 VW Beetle 2.0 engine is overheating. changed thermostat. Water is not pumped from reservoir but after car sits reservoir empties but not on ground so its going into engine. Changing water pump is next. What else could this be? temp light blinks and beeps hot. Sat overnight at work and when leaving, started car and temp light registed red immediatly. 8 hours it Sat. after changing thermostat light went out but after driving short distance light came back on. checked under hood and water in reservoir was boiling. The temp light has only came on two other times. That was when I had turned my air conditioner on this summer. After turning air conditioner off the light went off shortly after. I had no other problems untill car over heated on the way to work. Changed thermostat and looked at hoses and radiator but found no leaks by sight. after driving car 70 miles on the highway going uphill the car overheated: not in the red zone! but close! towed it back to home! now.... coolant slowly steams/ boils away in the coolant reservoir while driving around town or on the highway, it takes a while 30 to 40 mins. then the red chiming light comes on, telling me i need more coolant. i open the hood and you can smell coolant evaporating from the reservoir, usually about a liter gone? i dont want the car to over heat so i drive her home, i scared to take her on the road very far outta town, but i need to drive it to TX soon from AZ and back? not sure what to do next? what i have done 1st changed timing belt and water pump w/ metal impellar, 2nd changed out the themostat checked both new and old in boiling water both good!, 3rd checked fans both fans come on when the the car gets over the mid way 90, both fans run when the A/C is on? 4th checked hoses no cracks and both top and bottom hoses get hot! 5th replaced the temp sensor, 6th replaced the cap, I DONT KNOW WHAT TO NO NEXT? i think the car will over heat quickly if i the coolant boil and steam out?