Fuel Water Separator Rebuild and Flushing Fuel System
I just bought my '08 F250 with 140k on it. Runs like a top, drives great, and I love the truck. When I first inspected it I had failed to check the fuel/water separator while crawling under the truck. Once I got home a few days later I went to check it out and it was covered in diesel. The manifold (outter cover) had a crack in it at the bottom by the water drain. I purchased a whole new manifold unit, including gasket and drain **** for $150 from the dealer. I pulled it off, and noticed there was very little sludge in the bottom. I attributed this to leaking which would drain not only fuel, but the water collection too. Anyhow, after rebuilding it, I changed out the filters one at a time and bleed the system using the key on, wait until the pump stopped, then repeat 10 times between each filter.
Anyhow, after all was said and done, the truck fired up fine and no more leaks. I'm concerned with how sensitive the fuel system is to water and air trapped in the system. I read a post about a guy with water that had collected in the fuel cooler which voided his warranty at Ford when it damaged his HPFP and injectors. I don't have any issues right now, but to be on the safe side how can I flush the fuel system from the fuel cooler back to the tank?
I'm not entirely sure how the HPFP pulls fuel. Is the fuel system a linear loop, where the low pressure pump primes the HPFP, then it pressurizes the fuel rail and returns to the tank? If so, I assume the system is sort of self flushing then right?
I'm a maintenance fanatic and I know these trucks need it. Any tips on keeping the system in tip top shape would be appreciated.