Fuel Filter - Water Separator Question

[zielinski.family]

I have read several times through this forum as well as others that the Fuel filter only needs changing when the flow rate drops indicating there is plugging. If I understand right, the water separator is actually just a chemical treatment to the micron filter element. The question I have is, how long does the chemical remain intact before it is bleached of from the large number of gallons of diesel going through it. In the end, would the filter need changing in a shorter duration than just when flow rate drops for the sake of having the water separation work at optimum function? If this has been discussed somewhere before, please point the way.

 

[Burning oil]

IMO change it when the gauge indicates to do so. If you run really clean fuel then there is no need to R&R just for the sake of it, your filter is still clean.
Obviously you need gauge/s to know. If you run pre and post filter gauges you will not the pressure drop.

 

[schiker]

I think the owners manual says what twice? (maybe once) a year or 15K miles which ever comes first for the 6.5.

Not sure what the chemical treatment of the element is that blocks the water I think its a coating that keeps water from migrating into and through the fibers. As long as you use a water demulsifier additive the water droplets should be too big to pass the filter.

I think its something about the molecule size and surface tension of droplets of water not passing through. Not a chemical reaction with the element and the water. I don't think there is much to wear out or consume to this coating. But I guess everything wears out eventually.

Have you ever put water on a brown paper bag and it gets wet but still looks opaque but if you put oil on it it almost looks a little transparent. Kinda sorta like that oil and water have different properties. Water is heavier and has stronger bonds why oil "floats on top". AS long as you don't use a emulsifier additive oil and water won't make a solution is I think how you say it. You can mix them up like oil and vinigar salad dressing but they will seperate without emulsifier additive just like oil and vinigar salad dressing does sitting.

 

[Burning oil]

IMO change it when the gauge indicates to do so. If you run really clean fuel then there is no need to R&R just for the sake of it, your filter is still clean.
Obviously you need gauge/s to know. If you run pre and post filter gauges you will not the pressure drop.

Should have been "will know"