These biofilms, just like in your sinuses, lungs, bladder etc are complex and there are tests just like a doctor would use like immunoassays. Kind of surprised we don't see more people posting about fuel troubles. I change my filters yearly and carry spares, fingers crossed no problems so far.
Following is from a website aimed at fuel sellers:
"It includes bacteria, filamentous moulds and yeasts. They feed on the hydrocarbons in the fuel and create biomass, biofilms and damaging by-products.
These microorganisms will live very happily in even the smallest amounts of water, often from condensation, and at the interface of fuel and water, where they can create thick mats known as biomass. They can also coat surfaces and ‘climb’ up storage tank walls by creating what we know as biofilm."
Thank you again to all that have responded, I'm in Argentina now working on that ferry I posted info on.
Unless bio fuel added/blended to our pump fuel unknowingly I'm running "normal" #2 Diesel fuel, and when I travel away from home I do not used any bio-D marked pumps. Again I do not know if ever used in this truck by prior owners.
Someone earlier asked why did I go with Air Dog over factory filtration, part of my decision was based on the fact that factory filtration let me down in this instance, what about next time?
On my (2) 98 GMC 6.5s I got in 2000 & 2006 I built my own triple fuel filtration system and never had an experience I am experiencing such as what occurred here. The "sock" in the tank there is a 70 micron filter, which goes to my 30 micron Racor filter with aqua block treatment & WIF sensor, to the factory 6 micron nominal on engine, not quite apples to apples as the 6.5 is not Hp common rail only 3000peak Psi, vs 20K+ on the 5.9.
According to Air Dog engineering folks the "separator" on the AD is 20 Micron with a 2 Micron final before going to the CP3, when I commented earlier "overkill" I was commenting on the fuel delivery pressure/volume 165 gph is a LOT of flow for basically stock truck. I am a firm believer though in with today's ULSD and questionable fuel delivery, & storage methods one can not have enough filtration.
In a former life I was the ships fuel, oil, and water "King" responsible for all tests and treatment of the same including 621,000 gal propulsion fuel and 40,000 gallons aviation fuel for ships helicopters when one was assigned to us.
Our tanks were sea water compensated to maintain stability, as we used fuel; we filled tanks with sea water, the last 20% or so was just about unusable seawater/diesel fuel emulsion.
Which we could purify and use, but for every gallon of usable fuel 1.5 gallons or so waste water removed, or we recirculated our aviation fuel basically kerosene JP-5 to "polish" it clean through a big filter bank. Not to feasible for us to heat & purify our fuel before filling the tank, we have to rely on fuel transporters & storage tanks being "clean", some do better job than others.
This was part of my selection for the AD, system as it recircs part of the unused fuel from the primary "separator" back to the tank in a similar fashion as what we did to "polish" our aviation fuel.
What I was disappointed by with the AD was the physical size of the primary "separator" a small filter compared to the Racor I have on my 6.5s, which as to me is a lot to ask of a single filter, take care of all the "chunks" bigger than 20 micron and lose efficiency when plugged and possibly develop a small "hole" in the filter media and pass crap to the 2 micron (if rating is as advertised) that could also fail.
I suspect if I still had ability to test fuel passed through a single factory filter there would be cellulose material (filter media) in addition to "bugs" in the fuel. None of the engine mfrs to my knowledge put in a electronic differential pressure alarm to let you know when a filter is dirty.
Annual filter or mileage recommended interval is better than nothing but is not a true indication of filter blockage; as one can get a "bad load" of fuel at any time.
My Racor filters on my 6.5s are equipped with vacuum switches, & a second WIF sensor from the on engine water in fuel sensor that illuminates a red LED that blinks when getting dirty, or steady on when flow restricted so I know when filters are dirty.
My current set up on my trucks are going into year 4 now, the engine is protected and so is my wallet as I do not change filters unless they need to be changed. What I did not do on those and I will now think a way to do it, is use return to "polish fuel" like the AD set up does.
With all the comments read here, I have a spare new in box Racor 30 Micron filter assembly I think I will add in front of the AD so it will do all the "heavy work" in a larger bodied filter/aqua Bloc treatment, and add the 2nd WIF alarm & Vac switch feature to give some advance warning of fuel contamination, and defend the AD primary/secondary from having to deal with the large stuff.
I will also when I return to USA in a couple of weeks, be reaching out to some "fuels people" I know from Chevron etc. that I have dealt with over the years, to see if they can recommend a "best" treatment biocide.
Thanks again for allowing the discussion.
Tim
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