F250 7.3L Diesel Fuel leak problem

We have a fuel leak on our F250 7.3 L diesel. We tightened the fuel heater sensor and the fuel pressure regulator. These were both plastic plug in clips but there is still fuel leaking from (or near) the fuel heater clip. Can just the plastic clip be replaced or does the entire fuel heater unit need replaced?

Our 99 was intermittently leaking from the fuel filter gasket. Sometimes just poured out, other times wouldn't leak for days. I took it to garage and mechanic had it for a week before it started leaking again.