SailNet Community

SailNet Community (
-   Gear & Maintenance (
-   -   Cleaning Out a Diesel Tank (

Allanbc 06-19-2007 04:59 PM

Cleaning Out a Diesel Tank
What is the best way of cleaning out a diesel tank on a used boat?

RichH 06-19-2007 05:32 PM

If you have proper 'access' ports on the tank ....
Drain tank and take old oil home to burn in your oil heater.

Long handled scrub brush to knock the agglomerated particulate from the tank walls ..... sop up residue from tank bottom with paper towels, then burn !!!!!!
Then pressure washer, and pump the water/oil waste to a 55 gallon drum and let it gravimetrically stratify .... soak-up the oil that eventually floats on top of the oil/water mix with paper towel s (let the towels 'dry' then burn the towels) or use 'bilge boom' absorbant pillows (polypropylene fibers/matting rolled up into 'log) & discard at a recycle center (or burn).
Then ..... when the tank is visually clean, add a few gallons of NEW fuel and recirculate through a polishing filter @ 1uM rating (many times through the SAME filter).

If you dont mechanically remove the 'crud' from the tank walls first, all the subequent filtering/polishing will be very inefficient. You have to get the 'crud' off the tank walls FIRST.

Hope this helps.

hellosailor 06-19-2007 05:37 PM

Allan, because of access problems it often is easier & more effective to remove the tank from the boat. Then it can be cleaned out more thoroughly.

There's at least one long discussion about this either on this forum, or on Cruisers & Sailing Forums.

Gene T 06-19-2007 06:56 PM

The method stated is indeed the best method, if the tank is removable. Often it is not. Then one looks for alternatives.

Check if your area has a fuel polishing service. They drive over in a boat equipped with pumps and filters. Cost varies depending on access or what they have to do to get their wand into the tank. There is a crud that builds up on the bottom of the tank from dead algae that needs to be broken loose, pumped out and filtered. The clean fuel is then pumped back into your tank. Once it is scraped clean they will keep recycling the fuel until it is clean. Process works good if the person knows what they are doing.

I did this myself rather than paying someone else to do it. My problem started when the pick up tube in the tank was plugged by some loose crud. I removed the fuel gage sender which happened to be over the lowest part in the tank, good thing because this is where the crud is. I scraped the bottom with a copper tube as I pumped the fuel through it and into a makeshift filter made out of old t-shirts and gallon plastic jugs. Once filtered I poured the clean fuel back into the tank. I used an outboard bulb pump which worked fine, just tiresome and slow. This is somewhat dangerous, very messy, smelly and pretty unpleasant. It was however dirt cheap.

My engine was set up with 2 in-line filters, a Racor and the one that is mounted on the engine. I used a 30micron for the Racor primary. After this process I had no problems more problems, 5 years then sold the boat.

Now that I have had the experience I would hire it done.

mpraca 06-19-2007 07:29 PM

One alternative that will give you long term reliability is to install a bypass valve and a pump that will recirculate your fuel through the filter while the motor is not in use. Just leave it running for a few hours and check the filter if it needs replacement. That's cheaper than removing a tank and will get you out of trouble if you ever get contaminated fuel.

RichH 06-19-2007 09:32 PM

Sorry to disagree but a recirculation polishing system will not remove tank wall accumulated debris. It will only remove debris that is in 'suspension' in the fluid/oil.
A recirculation system will tend to keep the particles from adhering to walls as it removes them quickly upon their formation (as agglomerates of hard had 'soft' particles).

Dont waste time and money with a recirculation polishing system without FIRST mechanically cleaning the tank.

sailingdog 06-19-2007 10:05 PM

Biodiesel is said to have an effect of dissolving much of the crud in a diesel tank, so loading up with a batch of biodiesel or biodiesel/diesel mix and letting it circulate, via fuel polisher might do the trick.

Boasun 06-19-2007 10:11 PM

After you pumped the tank empty. Pressure wash with a solvent to clean the tank and then strip the residue into 55 gl drums and have an eviomental company cart it away.
Here in the southland, I had to have it done to a vessel I was working aboard. Pumped off 12,000 gl to a tank truck. Pressured washed the tanks then filtered the fuel as we brought it back aboard. The reason why? We went through a case of Racor filters in about 9 days, and as we was going back off shore the engines started losing power. Turned the boat around and refused to take it out until they clean the fuel tanks. After that was done, we changed racors about every two months or so.
Lesson? Pays to clean your tanks, especially if they had set for awhile.
You should have seen the crap we got out of the those fuel tanks and fuel lines. Don't forget to clean the fuel lines also.

Giulietta 06-19-2007 10:14 PM

OK...simple way...

Open fuel cap, its dark inside, so light up a match to see better inside and approach it......

Allanbc 06-19-2007 11:15 PM


Originally Posted by Giulietta
OK...simple way...

Open fuel cap, its dark inside, so light up a match to see better inside and approach it......

I hear that works better if you have gasoline rather than diesel. ;) Would you care to come and demonstrate that method? :p

Thanks to all the rest of you for the tips!

All times are GMT -4. The time now is 03:37 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
(c) LLC 2000-2012

For the best viewing experience please update your browser to Google Chrome