The O-rings are a serviceable part on the unit injector. O-ring damage can occur from improper installation or combustion heat, which could result in return fuel leaking past the O-rings into the engine oil or compression gases entering the return fuel. O-rings should be replaced whenever the unit injector is removed. Apply a thin coat of clean ethylene glycol to the injector O-rings and install them in the injector nut ring grooves. Make sure O-rings are properly seated, do not force them in place. On the Series 50/60 N2 injectors, the top O-ring is thicker and has a bright orange color; the middle and bottom O-rings are black and are the same thickness. See Figure "O-rings – N2 Injector" .
Figure 1. O-rings – N2 Injector
On the Series 50/60 N3, the top O-ring is orange, the middle O-ring is purple, and the bottom O-ring is blue. See Figure "O-rings – N3 Injector" .
Figure 2. O-rings – N3 Injector
|Unit Fuel Injectors and Unit Pumps Technician's Guide - 7SE500|
|Generated on 10-13-2008|