I have a 1984 300CD in which I have been running B100 for over a year and a half. This summer I was out of town and not driving the 300 CD now I am having a problem with clogged fuel filters.
I took the line off to the prefilter and pressurized the fuel tank getting about 3 gallons out that had small black balls in it. I replaced both fuel filters and noticed today a week later that the primary filter is clogging again.
Has anyone else on Bio-diesel had this problem and what did you do?

Thanks for the help!

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Moss Gate Bed & Breakfast
1985 300 TD GG done in by a red light runner
1984 300 CD Sold
2008 Titian
2000 Cadillac SLS
1966 FLH Sold
2003 Harley Ultra

Are you using rubber or Viton fuel lines?

Rubber will deteriorate fast with B100.

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'85 300TD "Puff The Magic Wagon" - Rolling Resto
'19 Mazda CX-9 Signature - Wife's sled
'21 Morgan 3-Wheeler P101 Edition
'95 E300d - SOLD
'84 300TD "Brown Betty" - Miss this one
'81 240D "China Baby" - Farm grocery getter

Viton hoses were put on about a year ago.

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Moss Gate Bed & Breakfast
1985 300 TD GG done in by a red light runner
1984 300 CD Sold
2008 Titian
2000 Cadillac SLS
1966 FLH Sold
2003 Harley Ultra

Biobor or Startron added to every tank will kill them.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

If dino diesel (regular diesel) was used for extended periods of time before you switched to bio, then carbon deposits build up in the fuel lines. Biodiesel acts like a solvent and cleans your lines out.

In general, it is recommended to run a blend to overcome issues of rubber degradation. The main thing is probably to make sure your biodiesel is free of water. Depending on the washing process, if water is still in the biodiesel I have heard of bad things happenning if running B100 that has water in it. Lot's of people have run B100 without issues though ... probably lot's more folks on this board that have more/better input than I do on this.

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Current cars:
1987 Mercedes 300D
1997 Turbo Nissan Maxima
2001 Lexus IS300 2JZ-GTE & 6 speed swap
2002 BMW E46 M3 - done ... needs engine management
2005 E55 AMG - mods started starts with a pulley and goes on from there!!!

Interesting.... I run B99 most of the time from a local supplier (Glover Oil).

Lately I have been running it in a blend because of all the driving we have been doing. I use the clear style primary filters and noticed them turning black when I started running the Bio in low doses. When it cleared up and most of the fuel lines were replaced I switched to B99 (over a year ago). That is odd. I'm interested to hear the outcome.

Have you removed the screen in the tank (or modified the screen). You said "the fuel hoses were replaced a year ago".... Did you replace the ones under the car at the fuel tank. What a about the rubber gasket at the tank screen.

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AJ

1985 300D (SOLD)

All the lines were replaced. I also pull the tank screen and clean it. I have pulled the tank screen since and it is still clean even through the primary filter is clogging.
I don't want to pull the tank since this is my daily driver. I will get some startron and see if that works.

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Moss Gate Bed & Breakfast
1985 300 TD GG done in by a red light runner
1984 300 CD Sold
2008 Titian
2000 Cadillac SLS
1966 FLH Sold
2003 Harley Ultra

I have had this problem.

It sounds like glycerin, or glycerides, coming out of solution in homemade bio diesel. It is often black and insoluble and gets stuck in the primary filter.

I have also seen algae from the tank dissolving in the bio diesel. It takes a while to totally dissolve.

I have about 50,000 miles of B100 experience, but I can't get it any more so I am back to dino for now.

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1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside

it sounds like algie to me - I've not had my 79 long enough to run much through it - but when i got it the tank was full of algie. The filters had what looked like black sand in them and the bottom of the tank had 3/4 inch of tar like sludge that needed to be cleaned.

I did what I could but I suspect I still have more in there.

In any case - black gunk in the filter sounds like algie to me.

startron tank cleaner, not fuel system conditioner.
and it's a bacteria/fungus, algae requires sunlight.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Where do you find "startron tank cleaner" locally? Is it OK to use with SVO?

Also, I may find this in future searches but will ask now for the good of all:
what is the best method to clean out your fuel tank in the home garage, or the most affordable professional options?

Thanks for any input!

These clogged filters sound like biodiesel dissolving years of coking on the engine and coming back through on the return lines. (As long as its a quality source of bio?) I would start with lesser blends and carry spare filters. That's what I had to do on my 1st wagon starting bio at its 280k mark. What y'all think?

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1990 300D 2.5Turbo, two tank WVO, daily driver 300,911
1992 E300 gaser, 150k. Parts only, For Sale

[B]1984 300TD Euro 4speed Sold
1977 300D Elsbett SVO single tank Sold
1981 300TD "Silver bullet" 285k ran B100 Sold
1981-5 300D x 5 cars stripped and reused, parts for sale

Other toys:
1995 Dodge 2500 Cummins 12V P7100 Bosch mechanical pump with 2 tank veggieconversion kit, only 120k!
1959 Cadillac Dad's legacy, needs finishing

Startron is available at West Marine, either in one of their stores or online. Last time I checked, there was a West Marine store in Raleigh on Capital Blvd. north of the 440 bypass.

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1987 300DT
2002 Ford F-250 7.3 Crew Cab Short Bed

I have had a "delayed cleanout" in higher milage vehiclces.

X2 for the delayed cleanouts.

After tuneups , during hot weather, long trips, etc.

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When the power of love overcomes the love of power the world will know peace.
Jimi Hendrix