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Old 11-27-2013, 08:06 AM
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Join Date: Jan 2013
Location: Lakes Region, NH
Posts: 179
So you think diesel fuel has problems...

The older I get, and the more I learn about fuel issues, the less I think I want to know. It turns out that home heating oil has a fairly large issue with "sludge" formation. Apparently the heavier petroleum components want to conglomerate and will eventually solidify. There are additives to dissolve sludge, and additives to prevent sludge, and additives to kill bacteria which feed on sludge. Since this sludge forms from heavier molecules in the oil, it's not like a sediment that gets filtered out. Instead it deposits on components when the fuel is at rest and motion free. It can build up so badly that gear type oil pumps cannot be turned.

Now I've worked on diesels for years and I've cleaned up a few dirty systems, but what we get is nothing like what can build up in the tank of a home system. I've been dealing with an issue that appeared to start after I added 40 gallons of B100 to a 275 gallon tank in '07. Finally, yesterday, I decided I needed to get this resolved once and for all. I almost wish I hadn't.

I have a 1 quart, 2 micron filter in line. The water heater flows .75 gallons per hour when it's running, approximately 11 minutes each run, maybe 10-12 times per day on the high end? So we're filtering 3300 gallons of fuel per year. The tank was new in '05 although the lines have been in service since '84 or so. The filter was installed approximately a year ago.

After fully servicing the burner I found no fuel to the pump. After a series of tests, I removed the filter to check for restrictions. It was packed full of "sludge." And yes, it looks very much like what you'll see inside an old diesel line or tank, but much, much thicker. The vacuum gauge on the filter had not indicated restriction, probably because the port to the gauge was packed with sludge. I know from experience that solvents such as acetone, laquer thinner, carburetor cleaner, MEK, and xylene are all effective at dissolving this deposit with varying degrees of success so I set about cleaning the filter in order to get hot water back for a day or so until I can pick up a new one. After visibly inspecting the lines at the tank and the filter, I am determined to "flush and clean" this system in the hopes I can end the two month cleanings now required to keep the water heater running.

The reason I'm posting this here is mainly for education. It's sometimes hard to get information about the differences between diesel fuel and heating oil. They're often thought of, and sometimes described as, very similar in many regards. This tendency to build "sludge" is a significant difference imo. I know that dispersants are added to vehicle fuel similar to what's added to diesel oil. These dispersants may play a part in keeping diesel from forming sludge. Or the refining process may be different enough between the fuels so diesel doesn't have the same tendency to form sludge. Home heating oil additive companies are as secretive about their ingredients as the vehicle fuel and oil additive companies. General talk of keeping molecules apart combined with references to surfactants and solvents are about all we get for clues. MSDS sheets give a minimum of safety information and hide much under proprietary formula entries. Patent searches may turn up more concrete information but I don't know that I'll spend time to dig further. Ultimately, I'm looking for a solution (one that will stay in solution) and I'm beginning to believe that buying a tank of diesel and applying for a rebate for the road taxes might just be the way to go. The diesel fuel price fluctuates more often than fuel oil so if I play my cards right I might even save money.

I wish I'd taken pictures. There were a few "Whaa??!" and "Wow!" moments during the inspection and subsequent cleaning.

When life gives you lemmings... make lemmingade.
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Old 12-01-2013, 02:45 PM
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Join Date: Nov 2013
Location: Honolulu
Posts: 47
Just to confirm, your issue is using B100 in a home heating system, yes? Having spent most of my life in Hawaii, I know bupkis about home heating, but I do have a lot of biodiesel experience. Not sure if you've run into this with B100 previously, but as mild and gentle as the stuff seems, it's one HELL of a flushing solvent. It's extremely common for a first-time user to deal with the plugged-filter issues during the period when it's degunking your tank and plumbing, and of course many of those people blame the B100 for clogging their system (correctly, in a sense - it's just that they'd not known to expect that).

If you have a good (reliable & cheap) source of B100 and it burns OK in your home system, you could consider progressive filtration - start with some el-cheapo coarser filtration to protect your 1l cartridges. I'm thinking I'd rig up drums with sock-type filters and circulate somehow. Might wanna roll up sleeves and degunk the whole tank in one nasty process, but I've got no idea what your access is like.

BTW, if there's any standard "rubber" in your home heating system, it's going to be softened and eventually fail from B100 exposure. Replace with alcohol-rated hose & seals as soon as you've got the chance. Conventional hose begins to swell and get "tarry" on the surface, at which point it's going to fail very soon from pressure.
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Old 12-02-2013, 08:12 AM
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Join Date: Jan 2013
Location: Lakes Region, NH
Posts: 179
Just to confirm, your issue is using B100 in a home heating system, yes?
Not quite. My problem started after mixing 40 gallons of B100 with 160 gallons of heating oil back in '07. After mixing the result would have been B20. I'm not blaming the BD for the problem although as you said, it might have flushed some buildup from the lines. The tank was new only a couple of years before and should not have been that "gunked" at the time.

BTW, if there's any standard "rubber" in your home heating system, it's going to be softened and eventually fail from B100 exposure.
Thanks for the advice. Heating oil systems are almost always plumbed through metal tubing. The only rubber parts I've found are in the pump cover gaskets (rubber/cork mix) and one O ring at the top of the tank to seal the float gauge.
When life gives you lemmings... make lemmingade.
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Old 12-02-2013, 10:02 PM
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Join Date: Aug 2005
Location: Oregon
Posts: 314
Some service companies can do in-place tank cleaning, even on full tanks. Possibly the most expedient way to get back to a clean baseline. Probably a good idea to get in the habit of using a reputable treatment on a regular basis afterwards.
Another possibility is to employ a floating pickup that draws from the top of the oil, rather than the tank bottom. That won't prevent additional buildup, but at least it will keep your lines and filters clean.
Last, you can stretch cleanout intervals by installing larger diameter lines and a larger filter.

'79 240D
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