1996 Toyota Camry • 223,000 miles

My camry constantly is out of anti freeze. I drive to work and back, when I get home it is almost empty and I dont know why. The head gasket, intake gasket, timing belt, and anti freeze was flushed. A mechanic just replaced those about a week ago and it is always low on anti freeze also when I get home to turn my car off it makes a bubbling sound. It doesnt seem to be leaking and the hoses seem to be on fine. Does anyone know what this could possible be? I have never heard of this before.
November 8, 2012.

Check the engine oil to make sure it isn't leaking into the engine, use a dye to locate the leak. You can get it at most parts stores. Add it to the coolant and drive. THen using a black light, look for leaks.