Background...

2008 F-350 6.4 KR CC
I purchased 18 months ago with 72K
Immediately changed all fluids and filters.
When changing lower fuel filter in HFCM, noticed a bit of slime in there. Cleaned it out and put in new filter.
I drain the HFCM every month or so, and not much of anything ever comes out.
About a month ago the DRAIN WATER SEPERATOR light came on. Took off valve, cleaned it, and established nice flow. It completely drained and some water came out. All was good for 3 weeks, now DRAIN WATER SEPERATOR light comes on every day, then goes off after about 5 min.
Decided to take the HFCM apart. Look what I found...



It was like a layer of Jelly or wax with lots of dirt trapped in it. All cleaned out, filters changed and running like a dream now.

What would cause this to form? Any clues?

 

Lack of maintenance. That's Paraffins that have built up. Filters probably weren't changed regularly, HFCM wasn't drained monthly and just simple lack of maintenance.

 

All of them, both 6.0 and 6.4, will look like that to some degree.

 

lack of maintance for sure!

 

Lack of maintenance or just SOP, looks like something to add to the bucket list for this summer, looks like next filter change I get a kit for the HFCM and see what hiding in there.

 

Wow, sorry to hear, your picture is a perfect poster child for maintenance with these trouble makers.

Drives me nuts buying used cars, one thing they slip on doing and nightmares for the new buyer.

 

I would not touch it if your draining flows well and your light does not come on.

Leave well enough alone.

I have never touched mine, rather regular draining is all that is needed.

 

Glad I saw this...

How long is typical for the drain to be left open when draining the HFCM? I drained mine, of course only fuel came out, but I let it drain maybe 5 seconds...long enough to put about 1/16" in the bottom of a 20oz water bottle. The stream that came out was very small...kind of like what you would see at the end of your garden hose with the spicket only cracked open. I was figuring I would see a stream that would come out the size of the outlet nozzle.

 

I drain mine for about 15-20 seconds. If it is steady with no bubbles I close it.

If it was not a strong stream then you may have an issue. come out the size of the nozzle.

 

Mine drains fine, wouldn't seem like should be a big deal, is there some 6.4 voo-doo involved.

 

No, I just don't believe in creating something when not needed.

 

The wild thing is.... If it wasn't making the sensor send a code, It really wasn't hurting anything there. It was a solid gel mass that really wasn't breaking apart. It was actually catching the larger pieces of dirt. It was way to thick and at the bottom of the pump in the bottom chamber. Could NEVER have gone to or through the filter.

My question is..... What made it? I only put Diesel Kleen in during the winter, besides that, just fill up once a week or so at a Shell station by my house..

tz

 

Just a natural build up is all. Wax and such.

 

What this is is Microbial Growth. This is common in diesel and jet fuel. It grows at the water/fuel interface and feeds on hydrocarbons. I have seen this in jet engine fuel controls and in my truck. If not attended to it will cause problems and eventually corrode parts. This is why I use Power Service Bio Kleen.

 

I think these should be taken apart & cleaned every 30k,
Regardless of # of filter changes. This crud WILL NOT DRAIN out - it stays stuck inside until opened up & Cleaned.

I agree with "If it ain't broke, Don't fix it" 99% of the time but this needs routine attention IMHO