Andrewwynn - thanks for your work on this. My son's car has approximately 150K miles, and it seems as if it would be worth a bit of preventative maintenance to both 1) replace the pump in the fuel sender and 2) replace the o-ring/washer in the siphon unit. If I understand things properly, you also placed a zip tie so as to prevent the plastic connections from getting skewed? I think I understand about the teflon tape to make a slip connection tighter, but my understanding is that teflon tape will be dissolved in gasoline. My understanding is that it may be OK when used in pipe threads where there will be essentially no contact with gasoline, but not OK when exposed to gasoline. A quote from another site: "inside the seal, it should never touch gas, in which case teflon is your best bet becuase it is clean and seals well. but gasoline is made up of 2 perticularly teflon breaking down components, benzene and cycloalkenes. benzene will dissolve the coherent bond of teflon and aluminum, and the alkenes will break down the chemical bond,y ou will be left with a white goo."

So if the teflon tape is going to dissolve, it seems as if a gas resistant o-ring is a better solution. However, I'm not sure I want to try to carve out a groove for an o-ring. What about a stainless clamp to give a bit of a squeeze to the joint?

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Stephen
2010 e70 35d- now driven by son #2
2005 e53 3.0 - now driven by son #1
2021 G05 45e PHEV - now driven by me
2008 ML320 CDI - driven by wife