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The Emphasis is on helping each other with diagnostic assistance, encouragement and the sharing of information
that will ultimately help us all become better at what we do in a positive and professional forum.
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It is, or should be common practice for technicians to drain the fuel water separator during regular services. We have discovered that some drain valves have failed to allow fuel and water to drain and in some cases the valves leaked from the vent at the top of the valve instead. We have once again discovered that water is reacting with the fuel, or something in the fuel, creating a whitish, greasy substance that builds up in the collection bowl. This substance does not flow and cannot be removed by draining the water separator. Below is a close up image of a water collection chamber in a HFCM from a 2009 Super Duty truck with a 6.4L PSD engine. The red arrow is showing the water sensor.
The result is reduced water collection capacity, blocked water drain valve ports, continuous water in fuel (WIF) warning light illumination and possibly an inoperative WIF light due to contamination of the WIF sensor. In a worst case scenario these conditions could allow water to pass to the engine fuel system causing driveability concerns, damage to the fuel injection system and even catastrophic engine failure. If you encounter a 2008 or newer Super Duty truck with a 6.4L engine that has a fuel water separator drain issue or a repeat WIF light concern it might be a good idea to remove the fuel conditioning module (HFCM) manifold to inspect the collection bowl for this substance and clean it out. Be aware that the rubber HFCM manifold gasket may have swollen or stretched and cannot be re-used. It is important to note that fuel samples from the affected trucks we have seen appeared to be clean ULSD but were not analyzed by a laboratory.
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Article by: Keith Browning Photographs by: Keith Browning
This article is only to provide information. It is hoped that it helps technicians in identifying possible
causes and assist in the quick diagnosis of the identified concern. This is not intended to replace any
official instructions, authorization or documentation of any Ford Motor Company Engineers, service manual,
TSB, Service Message or recall.
 FDDTS
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