How to Clean a Gas Tank

First I emptied the gas tank of about a gallon of what looked like gasoline. When I shook the gas tank I could hear lots of stuff rattling around inside. I figured now was a good time to take off the filler neck and the fuel level sender unit. This would allow me to see and retrieve whatever it was that was rattling around.

Well, it was the top part of a window cleaner spray bottle, lots of round pieces of cork and misc stuff. I got the feeling that at one time or another, a little kid was having fun putting things into the gastank. I was able to clean everything out. I could see through the filler neck opening that the inside bottom was covered in a sludge.

The question now was " How do you clean out the inside of a gas tank safely?". At this point, the tank smelled pretty strong of gas vapors which is a bad thing, and so I blew it out with my air hose. I also plugged in my shop vac on blow and let it run for 20 minutes. That seemed to work well. Another solution is to fill the tank with water and then drain. Don't work on the tank until it is safe!

Fortunately, the Nov. 2000 issue of Custom Rodder has an article on how to clean out a gas tank. It suggested using POR 15's Marine Clean and then sealing the tank with their Tank Sealer. Unfortunately, I couldn't find any at the local parts suppliers. You can purchase a fuel tank cleaning kit from Kanter's gastank webpage.

So I used what is used for cleaning out carburators - varsol. I poured in a litre of varsol and let it sit for about 3 days, occasionally mixing it around.

The Custom Rodder article suggested putting a large chain inside a shaking the gas tank vigorously. In my tank, there is a small pipe about the thickness of a pencil which goes from the fuel outlet to the bottom of the tank. If I did what the Custom Rodder article suggested, I would damage the pipe.

I purchased a long toilet brush to scrub the inside as best as I could. There was a lot of crud that came out with the varsol. It's not perfectly clean so just to be on the safe side, I will put an inline gas filter right at the fuel pump's inlet.

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Copyright April 2011 Eugene Blanchard