When the injector orings deteriorate on the OBS 7.3, does the oil always back up and blacken the fuel filter? I read that it does not on the SDs, due to the fuel system differences, but never found my answer searching for an OBS.

I'm still chasing an oil consumption problem on my 96 7.3. It has always used oil for the 5 years I have owned it, somewhat randomly. I've switched the truck from occasional use to DD now, so I'm keeping a close eye on oil levels and trying to fix the issue. I'm narrowing it down to the injectors... turbo is a rebuilt unit prior to my ownership, there is barely a wiggle in up/down motion and imperceptible in/out play, just a thin slime of oil on the intake side and charge pipes from the CCV, I believe, and the downpipe is dry. Blow by is minimal as well, truck has 230k now, plugged the CCV and flipped the oil cap and it does not lift, just rattles off. My fuel filter and fuel bowl is 100% clean. I've never cleaned it out and there was no sludge or anything to wipe out, looks brand new. I've been cleaning my AFE filter every 3k at oil changes, so it shouldn't be sucking excessive oil through the CCV. I'm thinking it has to be on the injectors, either an internal problem that is pumping oil into the cylinders, or a o ring leak. I don't want to waste the time swapping o rings if it isn't likely the problem since it isn't backing up to the filter, but if it's possibly the issue I'd rather spend 100 than 1200.

This issue really throws me for a loop because it isn't consistent. I'm on my 3rd oil change after switching it to a DD truck, and for the first 2000ish miles after an oil change, it barely burns any oil. Then it's like the flood gates open, it'll burn a gallon in a week (~200 miles). Sometimes it'll burn a gallon in a day or two. I've noticed the viscosity of the oil thins about that time, its more like water on the dipstick than oil, but doesn't spread on the towel like it has a bunch of diesel in it... maybe I should get an oil analysis to check though. Eventually I get tired of pouring money down a funnel, and just change the oil a few hundred miles early, and it won't burn oil for a while longer.

Oil is Delo, filters are Napa Gold, if that matters.

Thanks!