[C320-list] Pulled Fuel Tank Bio-Fouling

[Rich D]

Just pulled the tank on my 04 due to rough idle and what I thought would be
some water in tank and possible debris.  Also, noticed small diesel leak
through the top sender gasket and wanted to confirm it was not leaking
somewhere else.

What was in the tank was surprising.  Lots of water, and what I now believe
is microbial biomass.  It's white, hard almost mineral in appearance.  Grew
in and up corners of tank.  Pumping out diesel destroyed the cheap pump
that i bought to drain tank by clogging it 8 times, it finally died.

The hard biomass does not dissolve in water, does so in vinegar after 24
hrs.  does not easily scrape off.  My tank did not have inspection port, so
i'm not planning on adding one or trying to clean this one out.  I will
just order a new one.

I did leave fuel in the tank for 1 year when having the 320 shipped from
the west coast to gulf region.  That may have done it.  Also, noticed water
was coming down the fuel vent during a heavy rain.  I noticed some folks
here have added the water catch filter on the vent line, will likely do
that too.

What a pain.
Rich
04