TIL an old mechanic was right about fuel filters on 7.3s

I had a guy named Don at a shop in Omaha tell me to change my fuel filter every 10,000 miles on my 7.3 Powerstroke, no matter what. I thought he was being overly cautious since the manual says 15,000. After I let it go to 14,000 and ended up with a bad injector stutter on I-80, I realized he saved me a lot of headache. Has anyone else gotten burned by pushing fuel filter intervals too far on these old trucks?

3 comments

3 Comments

wren8261mo ago

Drain the water separator EVERY fuel fill up too, even if you think there's nothing in it. That little bit of moisture is what eats injectors over time, not the fuel filter itself.

robin_wright1mo ago

Did you check the fuel bowl drain valve orings when you changed the filter?

cole_robinson1mo ago

Yeah that drain valve oring is a HUGE pain point. I've had TWO trucks where that little O-ring dried out and cracked just from the heat cycling, then it starts sucking air slowly over time. The fuel bowl will look fine on the outside but you'll get that hard start or rough idle after sitting overnight. What REALLY gets me is people replace the filter and ignore that O-ring completely, then wonder why their truck runs like garbage a week later. I always tell guys to just replace that O-ring every other filter change at minimum, it's like a buck or two from the dealer and saves you a headache. If you're already in there draining the bowl anyway, might as well hit that valve with some fresh viton.