I had what I think is oil in the degas tank so I replaced the oil cooler. From there I replaced the water pump. I replaced the HPOP. I got a fuel bowl reseal kit to do. I flushed all the oil and coolant out during the oil cooler redo. So now I ordered new VC gaskets and pigtails as I found so many cracks in wiring and plastic blocks. While I had the VC off I checked the first injector and then ordered new o-rings for them all. New glow plugs and relay. There is not any coolant in yet!!! So my questions are, how can you tell a bad injector cup because I read online that if one is scorched black it needs replaced???? Also how to tell the difference between oil in coolant or diesel in coolant??? google will not search for pics of what I ask for. Thanks in advance.

Injector cups is the main goal here.

 

I wouldn't say there was one common clue to corrupted cups, save for the obvious fuel in coolant. You can have soot in your degas, and it could go unnoticed. You can have a crack in the cup... or not - the sealant can fail instead. You can have a crack in the cup, yet have zero symptoms if the sealant and the injector O-ring/copper washer hold.



My test: Pop all injectors out. Drain the coolant, particularly at the block heater. Leaving the degas cap on - undo the little hose on the driver-side of the degas bottle and plug it with a pen or a bolt. Spray some Silicone spray into each injector cup and use a rubber air nozzle to puff up the degas bottle to 15 PSI. The cap will vent if you try to put too much air in. Watch for bubbles in the cups.

 

Thanks , was just wondering what color fuel in the coolant is ? I really am new at this and do not know the diff between oil or fuel in the coolant. Thanks again.

 

Oil will leave black residue in the degas bottle. Fuel in the coolant, you should be able to smell.

 

Fuel (rainbow with a gas station boquet), and black oil spots. Oil alone leave a black ring around the edge of the degas bottle at the coolant level.




Soot from combustion gasses getting past the injector copper washer and the cups.




Aside from pulling the cap and looking for a black ring in the degas bottle, pulling a sample is helpful too.




Oil residue after draining.