Securing the fastener on the gas tank lvl sensor.
I recently removed/cleaned and inspected my fuel tank level sending unit. During disassembly I scraped off the "varnish" like substance that was being used to prevent the nut from turning that is on the treaded rod that keeps the unit together. I need to know what I can put back on the nut to make sure it does not come off. Would nail polish work submerged in gasoline, how about varnish. This was on the E320. thanks