Ok, going thru oil just a wee bit on my 94 C2500. Daily driver to work, I can go from the full mark on the stick to an 1/8th inch above the add mark in roughly 200 miles thru the work week. Engine has 149K on it, age of injectors/pump is unknown. NO drivablity issues, idles smooth, starts easily, runs on all 8, even after sitting for 10 hours in 20'F temps at work. yes she has blow by out all the normal spots, no leakage to the ground of oil or anything else. Just goes thru it. Using Shell Rotella T 15w40, which has what I have used in every diesel I have owned. Do I just put up with oil usage and start planning to replace the engine next spring/summer or am I missing something. I tried with the CDR vented to the ground vs hooked to normal spot with no real change in oil consumption. With my extension tube, I see the vapor, but there is no liquid oil in the tube or on the part of the frame where I have it mounted. A recent 400 mile trip at highway speeds took her from full to just below add. I get in the upper teens for MPG's. Truck is emaculate, was owed by a diesel mechanic before myself, body is 98% rust free, only a few small bubbles in the bottom of one door. My usual go to place for a rebuilt 6.2/6.5L is nolonger a viable choice from my recent research(Diesel Depot/Avant Salvage). Just want to look at all options before things get worse, I could trade it off right now if I needed to, just do not really want to. But I cannot also afford any long down time due to failure as its my way to work. Thanks for any ideas in advance