Fuel tank leak.

[Gazzaman22]

I'd say I rotated it half a turn, by tapping but now it's as tight as I can get it.

[white exec]

Is the leak from the seal, or the pipe connections?

[Gazzaman22]

Its seems to be coming from the black capping on and between the sender unit(yellow unit)

[Gazzaman22]

Pipes are drip free

[white exec]

Might be worth removing all the bits #8,5,2,6... and cleaning up with alcohol and drying off, and reassembling with the O-ring and surfaces coated with Hylomar Blue, which is fuel-proof. Hylomar Blue available on Amazon.

[Paul-R]

I would think long and hard before using any instant gasket product.

First thing is to clean everything up (pay special attention to the O-ring) and reassemble, providing there are no obvious cracks or distortions. If that doesn't work then same again with a new O-ring.

Be sure to remove any grit from the threads or sealing surfaces.

[white exec]

Hylomar is not instant gasket, Paul - it's a simple thin gasket/seal/O-ring sealer, much like Hermetite red, but more effective. Difference is that HB is fuel-proof. Thickness is not a lot different to vaseline. It also allows the joint to broken again, if required.

[Paul-R]

I've used both blue Hylomar and red Hermetite (and the green one as well) and concur that it doesn't set hard but it shouldn't be necessary is my point.

[white exec]

Agree, it shouldn't, but if there's some minute crack or surface irregularity, it might just remedy the leak.
Quite agree that a new O-ring should be fitted.

Interestingly, a Bosch recommendation for O-rings and cover seals in their diesel injection pumps is to lightly smear them with Vaseline before fitting. This does work: I had a weeping injection pump top cover, fitted a new (in-groove) rectangular gasket, and still a leak. Bosch technician here recommended the Vaseline and "nothing else". Did it on a new seal, and it worked.

[Gazzaman22]

Thanks for all the info lads. I'm actually blessed as I have a spare car for parts, so tomorrow I will take my leaky car to my old mans farm where the spare is parked. And clean up the all I can clean, and reassemble. If that doesn't do the trick I think should I swap all including sender. And see how that goes.. I would like the spare car to be operational as the old man still drives it down an old lane, to where his farm is. He uses it as his tractor!

[Paul-R]

Are the two cars exactly the same model? Same engine? Same model year? Petrol and diesel are different. Some diesel engines have different injection systems and will probably make for a different pump/sender unit.

[white exec]

Diesel engines usually have no pump in the tank, just pick-up/return and level sensor.
The O-ring (Fuel Tank Seal) is available from Citroen. Two types, depending on RP number.

[Gazzaman22]

More or less the same, yes a 2007 and a 2008 models, both diesel and 1.6, one has the sat nav package in it.

[Gazzaman22]

Apologies - I never updated this when I fixed to explain how I did. Yes so I did eventually get the black cap off and inspected the black O-ring. it had to be replaced as it was a tiny bit kinked, New ring sorted the problem. But my god I was lucky to get away with the hammer an chisel approach to the black cap ring..... It hasn't many notches left on it and it will be pretty hard to remove it again!

Thanks for the help

[Paul-R]

Haha, that's why there's a special tools for removing the locking ring. I also have worried when I've used a blunt screwdriver and hammer in the past.

Thanks for finishing off the post.