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TimSullivan · 02-26-2015, 06:52 PM

I notice that my diesel engine manufacturer recommends periodically draining sediment and water out of the main fuel tank. This is of course above and beyond changing out the multiple fuel and fuel/water separator filters. My DP has a 107 gallon diesel tank with a drain plug dead center on the bottom of the tank but I'm thinking it could be a bit dangerous taking that drain plug out and letting stuff drain out, especially if I had any trouble trying to reinsert that drain bolt with raw fuel gushing out.

Have you ever drained out sediment and water from your main fuel tank? If so how tough of a job was it and how ofter do you do this maintenance?

sknight · 02-26-2015, 07:02 PM

It's not dangerous, diesel is much less volatile than gas.

If you choose to do it yourself, let it run down to 1/4 tank or so, then use an oil drain pan you can get from the parts store. Loosen the plug, it will start dripping and try to be messy, once the plug is out watch it to see what comes out, clean diesel looks like honey, if that's what you get then you're good, if not then let it run till you get that, shouldn't take more than a gallon or two at most. Put the plug in and tighten it down, then clean up the mess where the plug didn't agree with going back in.

Or, if you get your oil changed, ask them to do it. I can't imagine they would charge much just to drop a couple of gallons of fuel out.

Dutch Star Don · 02-26-2015, 10:11 PM

Tim....I would recommend NOT doing it. The drain is threaded into a steel bung that is welded to the tank. Your coach is 15 years old and I'll bet that drain plug has never been removed. You'll take a huge risk of cracking the weld on that bung while trying to remove the more than likely rusted drain plug.

C-PHartley · 02-27-2015, 05:03 AM

Quote:

Originally Posted by Dutch Star Don

Tim....I would recommend NOT doing it. The drain is threaded into a steel bung that is welded to the tank. Your coach is 15 years old and I'll bet that drain plug has never been removed. You'll take a huge risk of cracking the weld on that bung while trying to remove the more than likely rusted drain plug.

I did mine after getting a bad load of fuel somewhere. After pumping and filtering 40 gallons for 4 hours, I was still getting trash out of the 100 gal. tank. I emptied the tank and removed the plug. The plug came loose with a little pull on a 3/8 inch drive ratchet, E Z peasey. My rig is approaching 30 years old and a 120 k miles. What I found was a black sediment had coated and sealed the hole over. I thought it was some kind of seal. Gently poking with a screwdriver broke up the crust and fuel ran freely with a surprising amount of trash that settled to the bottom of the catch pan I was using. I assumed that driving along agitated things enough to cause the trash to be picked up by the fuel pump where sitting still and filtering let things settle away from my pump intake. I thought this tank had to be clean now, right? Not so. I was still plugging fuel filters in 2,000 miles of driving regardless of how careful I was buying fuel or what biocide and fuel cleaner I tried. I thought maybe my tank is rusting inside. I ended up dropping the tank and found several handfuls of trash behind the baffles in the tank. My filtering had only cleaned the center section of the tank. I used water and high pressure air to flush the tank while tipping the tank at a high angle. In summary, 3 days of work and I had a clean and shiny (inside) fuel tank plus new fuel lines to the generator. Now knowing the construction of the fuel tank, I believe I could accomplished this almost as well with high pressure air, without dropping the tank. I'm a regular user of Pilot and Loves and only used large busy stations if in a bind. I guesstimate the tank weighed about 75 pounds empty. I hope this helps.

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