Cat 3406 B diesel on oil, fuel injectors check, what else can be?

My truck have diesel on oil, we allready change fuel injectors o-rings, what else could be? thank youCat 3406 B diesel on oil, fuel injectors check, what else can be?Could be a bad seal where the lines go through the head and onto the injector. Double check and make sure nobody left a line loose.
Cat 3406 B diesel on oil, fuel injectors check, what else can be?
well i'm not a diesel mech. but how about lift pump or cracked fuel port or hole in piston. does it smoke any. do compression test and test fuel port by air pressure. i liked to know too.