Diesel shouldn't look like this!! - PeachParts Mercedes-Benz Forum

tbomachines · #1 06-16-2009, 07:32 PM

I finally got my tank low enough to drain the rest of it out into a 5 gallon pail with the intent to clean the strainer. When I finished pulled to bucket out from under the car, this is what I found. Well I'll be durned if it ain't used motor oil!

Can't believe I was running this through the engine

snookwhaler · #2 06-16-2009, 07:55 PM

That is pretty black. I'm sure some of that darkness is due to the container. Have you put some in a mason jar to have a look? Do you always buy your diesel from the same place or at truck stops?

DeliveryValve · #3 06-16-2009, 07:57 PM

That is why I think it is important to run a 2 micron fuel filter just in case of issues like this. The stock fuel filter is like 10 microns. That will pass a lot of grime through comparably.

Here is a 2 micron fuel filter upgrade thread.

Lower Micron Fuel Filter Mod

Cr from Texas · #4 06-16-2009, 08:50 PM

Mine was getting black discoloration from a rotted return line. I'm still filtering out some.

ashedd · #5 06-16-2009, 08:54 PM

I have run a mix of 50/50 used oil and diesel in my SD several times. It's referred to as black diesel. It's more common than you might think. I never more than experiment with it(and WVO). You really need a centrifuge to remove any metal from the oil first. That is why I didn't mess with it too much. Car ran fine but did smoke a tad bit more than usual.

tbomachines · #6 06-16-2009, 09:00 PM

The bucket is all white plastic and it was completely clean before I put the diesel in it. I've only run one whole tank through the car since I got it because I haven't had it on the road until recently. The car is suffering from power loss (timed 23 seconds 0-60 today) and I'm trying to get to the bottom of it. This was after I determined there was fungal growth in the tank and got a bulk shipment of fuel filters, so I put in a couple ounces of soltron the other day and drained it today after a soak and short drive. The strainer was surprisingly clean, only had a bit of black junk on it, which I cleaned off. Unfortunately I still have power loss and hard starts so I think the next step is to replace all my lines...I have a feeling air is getting in somewhere. Still shocked at what came out of there though!!

OM616 · #7 06-16-2009, 09:03 PM

I came across this website while researching ULSD. It gives a possible reason as to why the diesel fuel and is filters are turning black.

Here is the link
http://www.wellworthproducts.com/articles/blackfilters.asp

This is one of the articals about the black fuel;

Have you seen filters that look like this?
(Mercedes Engine in School Bus - 3300 Miles)

There is a difficult new problem with ULSD fuels. Today most ULSD is derived using the process of catalytic cracking. This form of refining uses very high temperatures, high pressures, and chemicals known as catalysts to refine crude oils into various fractions including Ultra Low Sulfur Diesel. The fuels derived using these processes suffer from a wide range of problems including a lack of oxidative and thermal stability.

This lack of stability manifests itself in several ways including an increased ability to hold dissolved water, an increased negative reaction with oxygen, and a far greater inability to handle high temperatures over time. Different refining processes and catalysts can make these problems better or worse. It appears that certain refineries produce fuels which are far less stable than do others.

Diesel engines recirculate fuel to lubricate and cool the fuel system and engine components, In the past fairly large volumes of fuel were recirculated and this tended to keep temperatures lower, generally in the 140°F to 160°F. Today some of the newer engines can heat that fuel to temperatures that can exceed 200°F reaching even 220°F.

When some catalytically derived fuel is exposed to temperatures above 100°F for extended periods of time such as when fuel is recirculated in a diesel engine, the catalytic process starts up again re-polymerizing parts of the fuel. This results in rapid deterioration and darkening of the fuel. In this process small droplets of asphaltenes (heavy oils) are formed.

When the fuel is again pumped from the tank, the fuel filters will pick up the tiny asphaltene droplets, agglomerating them until the filter or filters are plugged. This can happen in as little as 3000 to 5000 miles with some instances of plugging in less than 1000 miles.
While there are additives that can add thermal and oxidative stability to fuels, they are not commonly used by refiners or fuel distributors. These additives are not found in most aftermarket additives.

Additives such Well Worth Products Summit do contain these additives and will dramatically improve thermal and oxidative stability while providing a wide range of other benefits.

tbomachines · #8 06-16-2009, 09:13 PM

Quote:

some instances of plugging in as little as 1000 miles

Only took about 40 for mine, I think I had some other problems!!

fruitcakesa · #9 06-16-2009, 09:14 PM

Regular biodiesel use in blends or concentration will keep the fuel system clean

sethyboy85 · #10 06-16-2009, 10:03 PM

I am fairly certain if you pull your injectors out you will find the heat shields almost caked full of carbon/soot = harder starts and down on power from poor spray pattern.

tbomachines · #11 06-17-2009, 12:39 AM

Quote:

Originally Posted by sethyboy85

I am fairly certain if you pull your injectors out you will find the heat shields almost caked full of carbon/soot = harder starts and down on power from poor spray pattern.

Yup, certainly on the list of things to do. Diesel purge didn't do anything for it, but then again it doesn't work miracles all the time. I've only got nailing on one cylinder though--considering the black hole that emerged from my tank, I think its not too bad.

Toblin · #12 06-17-2009, 12:55 AM

Quote:

Originally Posted by tbomachines

I finally got my tank low enough to drain the rest of it out into a 5 gallon pail with the intent to clean the strainer. When I finished pulled to bucket out from under the car, this is what I found. Well I'll be durned if it ain't used motor oil!

Can't believe I was running this through the engine

That looks like diesel with a good amount of deceased algae.

kerry · #13 06-17-2009, 08:20 AM

If you look at the thread, 'Engine not Firing' you will find a member with similar looking fuel. He also had power loss and a no start condition. His fuel turned black when just running a bottle of fuel under the hood. Recirculating it through the pumps and engine caused it to turn black like that. You may want to experiment with a soda bottle of fuel under the hood to see if yours does the same. His turned black even though the engine never started. Seems to me that you may have a common problem since the fuel looks the same and both of you had power loss. His is a no-start condition and yours is a hard start.
Does anyone know what would turn fuel black like that in short order just by circulating thru the primer pump, IP and return lines?

tbomachines · #14 06-17-2009, 09:43 AM

Quote:

Originally Posted by kerry

If you look at the thread, 'Engine not Firing' you will find a member with similar looking fuel. He also had power loss and a no start condition. His fuel turned black when just running a bottle of fuel under the hood. Recirculating it through the pumps and engine caused it to turn black like that. You may want to experiment with a soda bottle of fuel under the hood to see if yours does the same. His turned black even though the engine never started. Seems to me that you may have a common problem since the fuel looks the same and both of you had power loss. His is a no-start condition and yours is a hard start.
Does anyone know what would turn fuel black like that in short order just by circulating thru the primer pump, IP and return lines?

Thanks! I read through the whole thing just now, I feel as though that guy has some bigger fish to fry. I'm pretty sure mine was due to fungal growth in the tank since it was sitting for a while (though PO denied it). After dumping in half a bottle of startron it loosened it all up and started clogging my filters. Now I think that I am getting air in the lines coupled with at least one bad injector--and who knows how much stuff is caked on them now. Injectors are next big spending item on the list for me.

In the case of the other thread, it does indeed look like he is getting used oil in his fuel

or something, I'm puzzled by it. When I did a diesel purge, everything looked okay, though I should do another round soon. My starts used to be okay before I threw in antimicrobial and freed up all the little critters. Some (and it could be his case too?) probably got built up over the years in the lines, exascerbated by possible water contamination....

mikemass1221 · #15 09-29-2009, 08:55 PM

Hey Tbo- I know this problem has been resolved for you. But I have a 5 gallon bucket full of similar looking fuel. Here's the story. In my 1999 I tend to burn home heating oil, because I will get my hands on it where ever and when ever I can. (i.e people switching to nat gas and want their tank drained, I come over and pump it out to use in my benz.)
The 5 gallon bucket is just a sample of the last batch I got my hands on and what I think the rest of the tank is full of. (about 250 gallons) -- Dark dirty fuel. After doing some research, I guess I have the fungus/bacteria problem too. Probably a lot of build up and sludge on the inside of the holding tank where I store it (a metal 275 home heating oil tank). So here was my thought. Before I even think of putting it in my car, I'll treat it with a biocide or some kind of additive which you described to breakup/emulsify the sludge. Then I will run it through a filter using my transfer pump. Hopefully that will catch all of the sludge. Then I will treat entire holding tank with a fuel stabilizer, re-filter & then proceed to use in the car. Think that will do it?

Here's what I bought: Pri-ocide to treat the sludge problem & Pri-D to stabilize and "freshen" the fuel. I have used Pri-D for years and believe in it very much. It does what it claims to. That is why I decided to go with the same company and get the biocide treatment which is Pri-ocide, which I have yet to have experience with. I see you recommended Soltron or one of the other enzyme methods to kill the bacteria and break up sludge. Are these products basically all the same for this purpose? Here's a link to the Pri Products in case you are not familiar:

http://www.priproducts.com/