Is A Draining (Coalescing) Filter Necessary?

A coalescing style filter is a fuel filter which is designed to separate vapors, liquids, soluble particles, or oil from some other fluid through a coalescing effect. As fuel travels through the system, water coalesces (or builds up) on the outside of an element and then sheds to the bottom and drains when the system is shut down.


But do your filters really need this a coalescing style filter, and does it improve performance?

Truth be told, most of these drain-style filters are not capturing the water they were designed to stop. Instead, water passes right through the drain and directly into your injection system. No Bueno! That is the biggest reason why our partners at Fass stopped manufacturing their filters with a drain.


It is extremely important that the flow rating of the filter matches that of the pump. With a coalescing filter, efficiency tends to drop as flow rates rise. So Fass decided to make a change and went to a synthetic media with a water blocking filter and no drain. They call this the “Extreme Water Separator.”


Since the change, Fass Fuel Filters remove approximately 99% of water from your fuel and they do not have a coalescing drain. In comparison, the average competitor’s coalescing filter removes approximately 66%. Additionally, the extreme separator has also shown that it stops particulates down to 2 micron absolute in a single pass!


The extreme water separator attracts and locks water to it and does not let water drain to the bottom when the system shuts down. It is designed to keep the water locked into place. Therefore, a drain was no longer needed. With the new Extreme Water Separator, you can also rest easy knowing that your injection system is safe and efficiency won’t drop as flow rates increase.


If you want to improve efficiency and protect your injection system, take a look at our selection of Fass Fuel Filters and Pumps!