[Vwdiesel] External Leaking Nozzle Questions

[McCanless, James]

Last night on the way home from the in-laws, my son was driving the
rabbit and called me in the Jetta to say he needed fuel bad. We stopped
and the smoke came billowing out of the hood. I immediately thought
coolant. I have replaced in the last month, thermostat, water pump and
reworked the fan connection. It was not coolant but fuel. I filled the
tank with $1.94 diesel and back the vehicle up to get more light in the
engine compartment. Kyle fired the Rabbit up. The leak was where the
rigid fuel line enters the nut on the top of the injector. 

Is there a seal or o-ring that has failed or does the whole injector
need replacing?

TIA,
Troy