300SD fuel tank black sludge=clogged filters
I have been running WVO in my 85 Mercedes 300SD for about 6 months with no real problems. I live in Texas and today it was 40 this morning and about 70 degrees this afternoon. I run Kent's single tank system and am very happy with it. Since it has been cold in the mornings, I have mixed some diesel with the WVO, about half and half.
On Saturday I was going to go on a long trip (200 miles) so I had the car serviced and changed the oil (15/40) and the rear fuel filter below the tank (I use Kent's upgrade with the fuel pump at the tank). There was black gunk in the filter, but I had been running it for about 6 months, so I didn't think anything of it. When I set out on my trip I got about 50 miles and the filter clogged completely up. Had to replace it to get on the road again. I am now on my third filter in a week. They keep filling with a grey/black sludge that feels slimey, and doesn't react to a magnet (probably not rust, then). Any ideas what this crud might be? I filter my oil through three filters 20, 10 and 5 microns before putting it in the car. but the fuel filter keeps filling up. Any thoughts would be appreciated.
Ken
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Not uncommon
Hi Ken, your problem is not uncommon. I write about it in my SVO literature. Both biodiesel and WVO have an amazing scrubbing ability when it comes to cleaning the walls of an old fuel tank. What you are looking at is old algae growth that was probably built up in your tank before you starting running vegetable oil.
The steps to a solution depend on the amount of crud in your tank. Flushing with diesel can help but a permanent solution often requires removal of the fuel tank and taking it to a radiator repair shop to have it boiled out. Kent
How Hard?
How hard is it to remove the tank? Is it like most cars, just a few connections and tank straps and it drops out the bottom, or is it wedged up in there?
I have taken tanks to be vatted before. It costs about $50-$75.
Thanks
Tank removal
The tank comes out through the trunk. Remove the inside back panel. You will see the four nuts holding tank flange to the side fender wells. Drain tank. Disconnect hoses and remove the fuel tank screen. It is a tight fit and screen can cause interference when removing and installing. It may be stuck in place. Begin by prying up on left side flange to break in loose.
Algae in Tank
Hi Ken-
You may want to treat your fuel in the drum before you pump into car- I use a product called 'KILL EM'
see here-
http://www.fryer-to-fuel.com/store/product47.html
As far as the internal tank- probably worth a flush before it works it's way upstream so to speak!
Best of luck,
Diesel Don
Back on the road
Well, it took longer than I expected. Getting the fittings off the bottom of the tank was a huge pain! There was no way I could get the large fitting with the in tank screen off until I had the tank out. It was almost completely covered in that black tar-like substance you all have identified as 'algae'.
I took the screen out and once I washed it off, it looked OK. I thought I might upgrade to the larger outlet, but this one was working fine before it clogged up, so hopefully with a clean screen and new filters it will be OK.
The guy who cleaned the tank for me said there was not that much gook in there. He seemed to think it was mostly a rust issue. I had it done at a shop that does gas tanks and radiators. Cost: $40. The tank went back in a WHOLE lot easier than it came out. (of course, by then I knew where everything went and how to get it there) I just have diesel in the tank right now, and its running fine. I'll give it about a week or so, and put some more veggie in. Go Green!
Ken
Just curious
I was wondering about the whole 'algae' thing. I've never heard of a petroleum product that grows algae. It seems foreign to me. I could believe it grows in veggie, since it is organic, but not petroleum. Technically, I suppose petroleum IS organic - put down by dinosaurs millions of years ago, so maybe its not as much of a stretch as I think. None of the mechanics I spoke with had ever heard of such a thing. Of course, none were really diesel mechanics, either...
Thoughts? Comments?
More common in boats/ motor homes
This condition is probably more common in boats and other vehicles that sit for long periods of time without running. Old Mercedes diesels have often sat around for long periods before being "rescued."
Recommend you just do a google search on the topic - especially marine and motor home sites....
black sludge in filters
This black sludge is caused by water suspended in fuel, which turns to algae and shows up in your filter. This black stuff is actually (Bacteria) and yes it clogs filters. Once the tank is clean, use a marine microbro additive for diesel. This actually treats and kills the Bacteria. This solved my same problem. Consult with a Chemist knowledgeable in this area if further proof is needed.
My car is a 1982 300D with a 22 gal. alumunum tank mounted in the trunk for the SVO and is heated,I use a walbro marine diesel pump with a 7 psi pressure and monark fuel nozzles.I also use a diesel fuel/water seperater filter before the 6 way valve
from a 1984 volvo diesel.