1997 Audi A6 Thermostat

Your engine is the same as the thermostat on a 99 which I just answered. See further up the list ( front of engine pass side). Your problem sounds like one of a couple different things there is a steel coolant pipe that runs behind the engine connecting the heads together either the gasket sprung a leak on the back of the head or there is a hole in the pipe. There is also a coolant pipe that runs under the intake manifold on the pass side that goes to a o ring at the front of the eng pass side, either the o ring could be bad and water is running back to rear of eng or a hole in that pipe. You could have a leaking head gasket. Without seeing the car I can't be more specific, I usually add a dye and a blacklight with special glasses to find leaks good luck & let me know if I can help further