Nick,
The diesel is definetly your delivery valve o-rings. Cheap and easy......
Be sure to keep them covered while working on the rest and before you pull them out, clean around the area EXTREMELY well to keep any of that beautiful, black crud from getting into the injection pump

!
__________________
‘84 300TD “Mountain Goat”
'62 300d Adenauer-350 Chevy

- "Max"
'15 VW Passat TDI
'16 Dodge Ram 3500 - Cummins w/6-speed
'68 Mustang fastback
'55 T-bird
‘63 Studebaker Hawk