AWR-fix: Siphon pump repair

[wpoll]

Originally Posted by andrewwynn

The key is the right side should read the same (1.4 ish) down to 0.0 left


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Understand the theory but I'm not likely to try often it in practice!

1. Water is an BIG problem for CRDI engines (or more correctly, the mechanical fuel pumps in CRDI engines!) - and I don't want to find out there's a few hundred millilitres of water sitting in there!! Pretty certain there isn't - I have had the car down to a few litres before but I also don't trust all service stations - it's not unknown the get a batch of contaminated diesel - rare but not unknown.

2. I just paid well north of $100 for the 70L of diesel I just filled up with - the "sticker shock" isn't insignificant!

I'm just happy to see the right side stop at 1.4L while the left more or less matches what the gauge says.

[wpoll]

Originally Posted by wpoll

I'm just happy to see the right side stop at 1.4L while the left more or less matches what the gauge says.

For some reason, I feel like I need to qualify this statement.

The bit that is important here is not that the right side stops are 1.4L, it's that the left side continues to drop AFTER the right side stops at 1.4L. And that's the key, as andrewwynn has been saying. And has also been stated, you can be doubly sure the siphon is working well by letting the left side run down until virtually empty, as verified by the BC readings.

[sgrice]

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?

[cn90]

- My 2006 X5 M54 6spmT with 128K runs fine, zero issues.

- Should I do this "siphon pump" fix on a preventive basis?