fuel filter - PeachParts Mercedes-Benz Forum

cls67 · #1 03-01-2011, 01:20 AM

I bought my 86 300SDL about 10k miles ago. When I bought it I replaced the primary and secondary fuel filter. I drove it 2k miles home approx. On the way home I replaced the filters again since it was way too sluggish going up the Rocky Mountains. Again, a few months ago it got way to sluggish so I replaced them and again the car ran much better. After just about 3 months (driving 60 miles per day roundtrip to work) I had to replace them again.

I am assuming that I should not need to replace them this frequently. My guess is that I need to check the filter inside the tank for gunk/algae and clean out the tank if necessary. Does this sound right?

jonbobshinigin · #2 03-01-2011, 01:26 AM

Yes, it would be wise to get some Algae/Fungicide killer and put it in the tank. Then keep at it with the filters until it is gone. It probably is not the screen since it works for a while and then the filters clog again. You can take the screen out of the equation by swapping the fuel return and fuel supply lines and it will have no I'll effects.

kerry · #3 03-01-2011, 09:35 AM

I believe the product most people use to commit fungicide is Statron.

cls67 · #4 03-01-2011, 11:51 AM

Are you suggesting I might be able to get the job done by just adding the product without having to drain the tank and clean it out? If so, how long does it usually take? Thanks.

R Leo · #5 03-01-2011, 12:22 PM

Quote:

Originally Posted by kerry

I believe the product most people use to commit fungicide is Statron.

Biobor is another fungicide.

Ether · #6 03-01-2011, 12:28 PM

Startron will do the trick. How long depends on how bad the sludge is and how much Startron you use.

Read about Startron here:

http://mystarbrite.com/startron//content/view/12/34/lang,en/

R Leo · #7 03-01-2011, 12:35 PM

Quote:

Originally Posted by cls67

Are you suggesting I might be able to get the job done by just adding the product without having to drain the tank and clean it out? If so, how long does it usually take? Thanks.

How involved the process will be is pretty dependent on the level of contamination and that's almost impossible to determine without pulling the tank. I've had various diesel 'infections' and, because I'm 'lazy,' generally try everything possible first, short of pulling the tank.

If it were me, I'd prepare myself with an armload of filters, start fungicide treatment and base my success on 1) the reduced frequency of filter replacement and 2) the level of blockage in the clear pre-filter.

It may take several tanks of fuel/fungicide to get it under control. If you don't succeed, then pulling the tank and cleaning it may be necessary.

If you do have to pull the tank, DO NOT HOT DIP OR VAT THE TANK!!!!! It can destroy your fuel tank if it is hot dipped. Best practice is to pressure wash or steam clean the tank interior.

There is the possibility that it isn't a fungus at all but instead, a build up of paraffin on the tank walls that is getting cleaned off by the solvent action of ULSD or biodiesel. I had this problem with a 300D and had to pull the tank because fungicide wasn't doing anything for me.

cls67 · #8 03-01-2011, 09:10 PM

Thanks for the responses. The approach you described makes sense. BTW, are there certain types of stations I should seek out to purchase diesel fuel and certain types to avoid or does it make a difference?

vstech · #9 03-01-2011, 09:53 PM

Quote:

Originally Posted by R Leo

Biobor is another fungicide.

biobor is not approved for highway use.
and it's not good for vehicles. it will kill the fungus/bacteria, but it will not dissolve the bodies. it will CLOG THE DICKENS up in your filters!

vstech · #10 03-01-2011, 09:55 PM

Quote:

Originally Posted by cls67

Thanks for the responses. The approach you described makes sense. BTW, are there certain types of stations I should seek out to purchase diesel fuel and certain types to avoid or does it make a difference?

YES!
choose stations with a LOT of diesel purchasers! truck stops, and farm vehicle stops! the more turnover, the less time the tank has to accumulate water that harbors the buggs!

vstech · #11 03-01-2011, 09:57 PM

Quote:

Originally Posted by R Leo

There is the possibility that it isn't a fungus at all but instead, a build up of paraffin on the tank walls that is getting cleaned off by the solvent action of ULSD or biodiesel. I had this problem with a 300D and had to pull the tank because fungicide wasn't doing anything for me.

look in your filler neck for signs of vegetable oil buildup. check your cap for gunk, look in the clear prefilter for goop collecting.
if it's wax/oil sediment, you'll see it!

Ether · #12 03-01-2011, 10:00 PM

Quote:

Originally Posted by vstech

biobor is not approved for highway use.
and it's not good for vehicles. it will kill the fungus/bacteria, but it will not dissolve the bodies. it will CLOG THE DICKENS up in your filters!

That's why Startron is a better choice. The enzymes will devour the sludge and turn it into tiny particles that will mostly pass through your filters to be burned in the engine.

R Leo · #13 03-02-2011, 09:48 AM

Quote:

Originally Posted by vstech

biobor is not approved for highway use.

That's nonsense; check their website. Biobor MD is designed for both marine and over the road. JF is used in terminal storage and JF Aviation is for aviation jet fuel, an application one helluva lot more critical than use in a car.

Biobor JF contains arsenic and is an actual biocide/fungicide. Startron has naphtha as it's primary ingredient which only functions as a water emulsifier/dispersant and is not considered a biocide.

Quote:

Originally Posted by BioBor

Applications–Biobor® JF is used by a large number of aircraft manufacturers, airlines, marines, trucking fleets, railroads, bulk storage terminals, fuel suppliers and by other users of hydrocarbon fuels and oils exposed to the possibility of contamination by fungus and bacteria.

cls67 · #14 03-02-2011, 12:28 PM

I put in two ounces of StarTron yesterday before filling up my tank. Well see how it goes.

cls67 · #15 03-16-2011, 12:05 PM

The stuff actually works. My acceleration was way down even after changing fuel filters. I put in 1.5 ounces of StarTron when I filled up the 2nd time (2 ounces on the first run) and about 2/3 of the way into the 2nd tank the acceleration went up dramatically. I could barely get up my driveway before (which is pretty steep) and now it shoots right up.

It is interesting to me that neither Mercedes mechanic I have spoken to about the problem recommended the product and I had to find out about it on a message board. The out of state mechanic who inspected it for me just said to change the filter if necessary during the drive home (2200k miles). Once I got home the mechanic suggested dropping the tank and cleaning it. My guess is that they don't like the idea of customers saving money instead of giving it to them.