HFCM Filter Change

[jjakicic]

When I last changed my 2008 F450 (6.4L Powerstroke diesel) HFCM filter, I started by draining a full quart of fuel through the water separator drain. After removing the old filter, diesel fuel continued to spill from the HFCM until I could screw in a new filter. I'd bet I lost a good gallon of fuel. What a mess! Shouldn't the fuel flow stop upon removal of the old filter? What did I do wrong? Thanks. J.J.

[sinner6.0L]

Try changing the filter with less fuel in the tank. Around 1/4 tank should stop any unwanted flow.

What happens is the fuel siphones out of the tank when it's at level that would put it above the HFCM. Same thing happens when you change the actual HFCM. In that case you always need to cap the lines

Believe me. I've had many diesel baths due to the 6.4 horizontal filter. It tests your sanity that's for sure

[jjakicic]

Interesting. The first time I changed the HFCM filter, diesel didn't flow out of the device. But I can't remember how full the fuel tank was either. Seems like Ford should have made an allowance for this issue. Shouldn't they have incorporated a shut-off valve to prevent fuel from flowing from the tank when changing the filter? Thanks sinner6.0L!

[timid1]

I've changed the fuel filters on my 6.4L more than a few times and have never had the problem others seem to have. I start on the engine mounted filter first (I don't change it, I just open it), then I drain the rail-mounted filter until there's nothing left, and then change the rail-mounted filter, then last the engine-mounted filter.

Probably has something to do with the ORDER in which the filters are changed more than the amount of fuel in the tank. I'm sure there are check valves, and by not undoing your engine-mounted filter first, you're getting all that fuel.

Hope that helps.

[jjakicic]

Glad to hear you haven't had fuel drainage issues timid1. How full has your diesel tank been upon changing filters? Mine was easily 7/8's full when I had continuous flow out of the HFCM. It was unstoppable!

Another hint I have read is to put the F450 front end up on ramps to get the HFCM up higher relative to the fuel tank. The Ford Owner's Guide Supplement for the 6.4L diesel actually says to change the HFCM filter BEFORE the engine mounted one. Well, that doesn't work!