FMB, from his description, I think the injector is leaking externally- spewing fuel onto the top of the head inside the valve cover, not into the cylinder.

If the truck is under warranty, that might be the way to go, but it looks like he has some mods...

Once while helping another guy with a problem with a cummins in a big truck, we actually started the engine with the valve covers removed in order to diagnose a problem. It really didn't sling oil much at all.

I was going to suggest starting it to see which injector is leaking, but I wasn't sure it would be safe (fuel of that high pressure could inject through skin, and would also spray in a mist that would be easy to set on fire). Since djgaston was talking about upgrading with a set of performance injectors, I figured determining which one of his stock ones is leaking was moot...

 

Jeff, it sounds to me it could be either, if it was external, it would be easier to find. As for warrantee, it is good till till 5 years/100k miles but it sounds like he doesn't want them to touch his vehicle. If I remember correctly, someone on this forum wrote about leaky injectors on warrantee and ended up with a new engine. Of course, if the dealer saw any performance upgrades they may not allow warrantee work.

 

I'm sure not an expert, and you probably know more about these cr engines than I do, but if it were leaking into the cylinder, wouldn't it be knocking?

Anyway, I agree if it can be a warranty issue, it could be the smart thing to do, even if he upgrades later. With that much fuel in the oil, I would think there would be a risk that it could trash the turbo, or maybe even spin a bearing or something...

 

I bought a Toyota car a long time ago, of which I was told it had a transmission problem. I test drove it and it indeed had, but I also discovered that it had a busted FP diaphragm. I ended up driving that car with twice the oil level for good half hour, oil diluted with gasoline! Once I noticed it, I repaired it with no more driving.
The car's engine did not take any damage, I put another 90 k on it and it never smoked or spun a bearing. The upside was, the gas/oil mix washed the crankcase so well, my oil remained beautiful transparent in color for three oil changes after that.
What I am trying to say is, I would not write off that engine just yet.
-P