97 A4 Quattro 2.8L Auto - major coolant leak
 

Hello, son's car has a major coolant leak somewhere at the back of the motor, I can't really spot where (car is not at home unfortunately, but the thing is leaking so badly it will need a tow).. seems to be more toward the passenger side.. Is there anything to suspect first? I think there is a crossover line back there, and the coolant sensor is in it.. Not sure where the heater hoses enter/exit the firewall, maybe they are back there also? I am trying to decide if I can tackle this myself, but access to that part of the engine seems very limited.. any insights are appreciated..

Yes the crossover pipe is one good source. The heater hides come out of the firewall in the center of the car, inboard of the battery. They may have a rectangular loom covering them. I think you're probably on the right track with one or the other of those.

thanks.. is crossover pipe plastic? dealer item?