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I pulled my fuel filter today to replace my FPR guts and found this:
My gut tells me it is injector o-rings as I have 175k and they are original. Fuel filter has about 10k miles on it. I've been losing 3-4 quarts of rotella T6 5w-40 synthetic every 5k miles.
Thanks for the replies. I'll put an order in at Riff Raff soon. This black filter and eating oil are my only symptoms. Starts easy hot or cold. No smoke at cold start.
I also have the stock fuel return setup not the FRx. I have read that a dead end fuel setup should not allow oil back into the fuel bowl. If this is true, how did my filter get black?
When I've changed filters they always look similar. And like you have read, and I have read, unless you have a regulated return or the Riffraff FrX leaking injector o-rings won't cause a black filter. It will on an OBS though as those engines didn't have deadended fuel gally's in the head.
If the check valves in the heads aren't closing properly it could conceivably feed oil/fuel mix back into the filter housing when the engine is shut down.
i know for a fact that a stock fuel system can drain oil back to the tank. i worked on a city owned 7.3 2002 f-250 stock truck and any injector oring was bad and when i got to it there was 15gals of oil in the tank. 2500psi will go past 50psi.