Question re: 2001 C5 V6 fuel pump leak

[sonoramicommando]

Hi
I have petrol leaking and pooling on top of the fuel pump. It's not obvious where the leak is coming from. I suppose it is possibly leaking from fuel hoses ((quick connecting coupler) or fuel pump/tank seal but can't confirm. Are there any other possibilities?
And what's the most common area of failure?
If quick connectors failed, is it necessary to replace the entire section of the fuel line?


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[Mandrake]

Quick connectors are unlikely to have failed but might need greasing and re-seating as the o-rings can dry out.

Make sure the fuel pump is disabled (remove fuse etc) and crank the car for a few seconds to release most of the pressure. Then disconnect the connectors, (cover with a thick rag to catch any spray) clean them and apply some lithium grease on the spigots then refit them. They should slide on smoothly and lock with a nice click. If they don't, try removing them and re-fitting a few times so the grease can get to the o-ring. If they don't seem to lock securely they may need replacing. Sometimes dirt can get in the release tabs stopping them from springing back properly, so you might need to clean them.

[sonoramicommando]

I'll give that a go - I tried disconnecting hose without relieving pressure earlier today - bad idea... [emoji12]


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[sonoramicommando]

ok I've undone the fuel pump holddown fitting and can't get it back on the threads. is this typical? I couldn't get it on last night so drove to work with the pump semi attatched just floating about and there was no pool of fuel.


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[xantia_v6]

ok I've undone the fuel pump holddown fitting and can't get it back on the threads. is this typical?

Normally a sign that the rubber ring is not seated correctly

[sonoramicommando]

ok I've undone the fuel pump holddown fitting and can't get it back on the threads. is this typical?

Normally a sign that the rubber ring is not seated correctly

not sure that's it - I even tried without pump and seal and still same problem. It's either keep spinning or go on slightly crooked then gets stuck.


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[Mandrake]

Did you grease the rubber seal and the threads of the ring ?

[sonoramicommando]

Did you grease the rubber seal and the threads of the ring ?

no - would it make a difference?

[Mandrake]

On a large, coarse plastic thread, yes.

And the rubber seal will be quite grabby when trying to tighten without some grease.

[GiveMeABreak]

Should the title read 2001 C5 given the C6 didn't come out until 2005? Could be confusing for those searching.

[sonoramicommando]

Should the title read 2001 C5 given the C6 didn't come out until 2005? Could be confusing for those searching.

you are so right - you must excuse me, I have been inhaling copious amount of petrol fume today

On a large, coarse plastic thread, yes.

And the rubber seal will be quite grabby when trying to tighten without some grease.

just to be clear, the seal sits on the very top of the threaded spout, sandwiched by the fuel pump, correct?

[Mandrake]

Yes, the rubber seal goes on first, then the pump is inserted through the seal, then the threaded ring last.

As well as greasing the seal and the threads, make sure you push the pump body down firmly before starting to screw the ring on - the pumps are usually spring loaded such that the bottom of the pump is held against the bottom of the tank with a spring, and the threads on the ring are quite short, so if the pump isn't pushed right down you won't be able to get the thread on the ring started. You need to keep firm downwards pressure on the pump and threaded ring as you are trying to screw the ring down.

For what it's worth, when I swapped a Xantia fuel pump a couple of years ago I bought a brand new seal and new threaded ring - both from Citroen, and I was completely unable to fit the threaded ring even after about a dozen attempts - it was very reluctant to start on the thread and when it did start it would either cross thread, or turn about 1/8th of a turn then jump off again.

In the end I re-used the original threaded ring (but with the new o-ring gasket) and it fitted perfectly first time. So something was out of spec with that new threaded ring...

[lexi]

Are we in agreement to the use of Lithium Grease? I normally use Red Rubber grease or Silcone Grease for rubber.
I don't mind if Lithium is good as I have loads of it.

[xantia_v6]

Are we in agreement to the use of Lithium Grease? I normally use Red Rubber grease or Silcone Grease for rubber.
I don't mind if Lithium is good as I have loads of it.

You should be using something that won't poison a catalytic converter... I would suggest engine oil, or a mineral oil with no additives.
I don't know if any commercial greases are rated as cat-safe.

[Mandrake]

Are we in agreement to the use of Lithium Grease? I normally use Red Rubber grease or Silcone Grease for rubber.
I don't mind if Lithium is good as I have loads of it.

You should be using something that won't poison a catalytic converter... I would suggest engine oil, or a mineral oil with no additives.
I don't know if any commercial greases are rated as cat-safe.

The two different issues here are whether the grease is safe for the o-ring and whether its safe for the cat.

For the o-ring itself I can't see any problem with lithium grease - the o-ring is not going to be natural rubber when it is exposed to petrol or diesel. It's obviously going to be a petrol/diesel/hydrocarbon/oil resistant material like Nitrile or Neoprene. For such a material a standard lithium grease with no added extras is going to be a lot easier on it than the petrol or diesel it's designed to seal against...

I've routinely used lithium based greases on the hydraulic system in LHM Citroen's with no issues at all with the seals, which are also designed to be oil resistant and probably a similar material to the fuel pump o-ring.

For the cat, the two main sources of poisoning are lead and silicone. So any silicone based lubricant is an absolute no-no lexi. I don't know what the ingredients of "red rubber grease" are so can't comment on that one.

I think its very unlikely that a "standard" no added extras lithium grease would have any ingredients in it that would be harmful to a cat, but if you can find any references that say otherwise please post them.