Fuel tank cleaned!

My fuel tank is now clean. I obtained a 5 gal tote of biodiesel, and then ran my tank down to empty (on the freeway, which sucked, I had to pull over and put in a couple gallons to get moving again). Today I opened the drain plug in the tank, pulled out the sender unit, and drained everything. I wasn't parked on a perfectly even surface, so I had to use my 12v accessory pump to suck out the remaining fuel. There were 2 gallons of really lousy fuel. Water, glycerin, and some rust. The sender unit on this aft-of-axle 37-gal tank is 6" in diameter, so I was able to see in the tank, and also to get my whole arm in there, to wipe off the inside with a clean rag.

The tank wasn't rusted really badly, just a few spots of rust starting at the welds for the drain plug, and a thin layer of what looked like rust (but could have been residue of melted rubber fuel hose) on the baffles. I cleaned it all up as thoroughly as I could.

The tank is an interesting design: it has a spiral baffle, a few inches tall, that leads up to the sender unit. It's galvanized steel, which can get destroyed by bacteria that grows in water in biodiesel and attacks the zinc-- but in this case I hadn't much corrosion. The biggest annoyance was the glycerin and water from some bad fuel I bought last year from a guy who made the stuff in his basement. Nowadays I buy only ASTM approved biodiesel from any of the three commercial retail filling stations around the Bay Area that carry it. The right thing would be to use a plastic tank, which I now own and will eventually install.

I feel much better having this tank clean. The stock filler hose was rubber, and it was weeping fuel from a joint between the filler cap and the tank. So I threw it away and replaced it with a new vynil 1.5" ID hose.

I RTV'ed the cover for the flywheel-- the stock paper gasket had disintegrated and Ford doesn't sell the gaskets anymore. That might help me track down leaks better. There's still a very small leak or two on the engine, as well as the transmission and differential seals. I'm on a long-term mission to have a leak-free vehicle.

In a perfect world, I would have done all this BEFORE starting to drive the vehicle with biodiesel. Instead I deferred it for 10,000 miles, which isn't a lot. It's getting done though, and that makes me feel a lot more confident.