Why is my oil black?

[Waterloo]

Thank's Rawze, I poked around, did the overhead, fixed that front cover leak, new AC compressor and am still perplexed about the oil. When I found I could blow through that sensor, I figured that has to be it, only thing I can figure as everything else looks good.

The YTS turbo is spotless and slobber free. No oil anywhere, unlike the two previous cummins reman turbos at double the cost.

We shall see what happens, I just had the truck serviced so time will tell. I'll get that oil sample, will order a cup online and send it in, see what the results are. Any recommendations?