so i succeeded in getting scolded for spilling a bit of diesel on the sidewalk..

but the reason i took out the tank was becuase there was fuel leaking into the trunk and actually pooling there.. i'd mop it up and it'd slowly get worse.

on getting the thing out, i had to actually locate the source of the leak, which i am still in doubt about even after extended close examination. here's what i saw:

the vent and the return line was totally dry. the filler neck was somewhat damp with fuel underneath, the rubber boot on the filler neck was partially destroyed, the spilled-fuel dump line was soaked but appeared intact (the line that runs through the trunk space and empties out stright down, in the wheel well).

a week ago, when i found this problem initially, i looked underneath and found the fuel tank output hose (the rubber hose part with the metal gasket that connects to tank filter head to be totally soaked, but the tank filter head itself, and where it contacts the metal of the tank, to be totally dry. so i ruled out its o-ring. but the fuel output hose was cracked, and when i replaced it and drove another 600 miles, it stayed dry. however, the leak to the trunk persisted.

so the question is this: does the leak have to be on the filler neck, in order for there to be fuel there? the tank cap o-ring looks fine. it doesn't look like it's running down there and causing the mess in the trunk - could it run even though it appears to be only damp? is there another seal down at the bottom, besides the filter's o-ring and the output hose? it even looked pretty wet near the right two bolts holding the tank in place: could the tank itself be leaking where the two halves meet? (the tank consists of two moulded halves welded or otherwise glued together i looked hard but nothing more than the vague dampness that covers the whole bottom and right side (standing behind the car) of the tank, including the bottom of the filler neck.

the tank filter was covered with an even coat of black stuff, but was not clogged. i can't tell to what degree this black stuff covers the inside of the tank.. at least the bottom of it. it's not green, anyhow - is it algae? the fuel appears to have a greenish-red tint (impossible i know, but when i shine a light inside, i see both colors). i put is some dieselkleen, i dont know if that could cause change in color.

how can i determine if the tank itself is leaking? how can i fix it if it turns out to be?

yes this is an original Granny D garaged '81 240D, which i am proceeding to gut and probably go for SVO. free and harmless fuel is ok with me.


thanks guys and gals

- jeff

tokeland, err oaktown, CA