Progress report - no progress!
Well, I've checked everything carefully and also replaced the locking cap with one that has a better rubber gasket that presses more strongly.
Net result is no change!!
The cap seems to be sealing. There are no leaks behind the rear mudguard at any joint between the filler and the tank, or the overflow pipe, but on left corners fuel is emerging into the fuel cap cavity behind its flap, running out of the drainhole and then seeping down the fuel filler pipe to spread under the tank itself. All joints at the back are tight.
The only remaining joint that I can't check seems to be between the base of the body that accepts the locking cap and top assembly above the fuel filler pipe. That is between the base that is attached with four screws/bolts to the bodywork and the locking cap base itself, which seems to be secured to the fuel filler base with two small screws but which I cannot move even when the two screws are removed.
I can't find a diagram of this assembly and don't want to butcher it.
Has anyone dismantled one or, better, photographed one? Has anyone cured this malais?
All advice most welcome.
And Happy New Year to all.
JohnW
CX petrol smell - still trying to fix overflow!
Moderator: RichardW
Hi John.
The culprit has got to be the collar that is fitted to accept your locking cap!
It sounds like everything in the rear wheel arch area is dry and secure [including the breather pipework] before there's any overflow from the filler cap aperture. You've also determined with securing it's seal the locking cap does seal onto it's collar well.
But the locking cap's collar is the weakest link as this fits around the existing non locking collar. If this doesn't seal the fuel will pass through by vapour although to get a splash I'd you're either filling the car well up to the cap or the car's being cornered hard!!
The two small self tapping screws locate the collar merely to stop if swivelling and when they are removed it should swivel off as though it's the normal filler cap; it wont just pull straight off.
It's een a good few years when I last changed one on a Cx but mine did have a crack in the plastic collar the filler cap screws onto and it fumed strongly too. As an experiment can you get a non locking cap sealed back on as it would be standard from new.
Hope this helps.
Andrew
The culprit has got to be the collar that is fitted to accept your locking cap!
It sounds like everything in the rear wheel arch area is dry and secure [including the breather pipework] before there's any overflow from the filler cap aperture. You've also determined with securing it's seal the locking cap does seal onto it's collar well.
But the locking cap's collar is the weakest link as this fits around the existing non locking collar. If this doesn't seal the fuel will pass through by vapour although to get a splash I'd you're either filling the car well up to the cap or the car's being cornered hard!!
The two small self tapping screws locate the collar merely to stop if swivelling and when they are removed it should swivel off as though it's the normal filler cap; it wont just pull straight off.
It's een a good few years when I last changed one on a Cx but mine did have a crack in the plastic collar the filler cap screws onto and it fumed strongly too. As an experiment can you get a non locking cap sealed back on as it would be standard from new.
Hope this helps.
Andrew
Andrew,andmcit wrote:Hi John.
The culprit has got to be the collar that is fitted to accept your locking cap!
It sounds like everything in the rear wheel arch area is dry and secure [including the breather pipework] before there's any overflow from the filler cap aperture. You've also determined with securing it's seal the locking cap does seal onto it's collar well.
But the locking cap's collar is the weakest link as this fits around the existing non locking collar. If this doesn't seal the fuel will pass through by vapour although to get a splash I'd you're either filling the car well up to the cap or the car's being cornered hard!!
The two small self tapping screws locate the collar merely to stop if swivelling and when they are removed it should swivel off as though it's the normal filler cap; it wont just pull straight off.
It's een a good few years when I last changed one on a Cx but mine did have a crack in the plastic collar the filler cap screws onto and it fumed strongly too. As an experiment can you get a non locking cap sealed back on as it would be standard from new.
Hope this helps.
Andrew
Certainly does! The locking cap's collar turns to come off I take it - I never thought of turning it and neither of my manuals is the slightest help of course.
I'll get into it in daylight (9.40 pm here) and provide feedback. Most grateful.
Cornering hard? Me? Well the car does invite it..... It's a 1980 C-matic Pallas with Diravi.
Much obliged.
John Waterhouse
maybe your tank breather is not breathing so the tank is presurising and pushing fuel up the breather tube in the filler neck,and andrew is corect when saying the coller that the cap fits to dose rotate and come of if the fixing screws are removed,there should be a corck seal between that and the top of the neck
regards malcolm
regards malcolm
Right, replaced flimsy neoprene found behind the collar for the locking cap with 3 mm thick rubberised cork and out for a vigorous test. Fuel everywhere!andmcit wrote:Hi John.
The culprit has got to be the collar that is fitted to accept your locking cap!
Hope this helps.
Andrew
Replaced locking cap with locally purchased device that fits (but doesn't cover the screws that fix the locking collar) and out for a test. Not a drop. Looks like both gaskets were leaking! Now to disguise the screw heads......
Thanks to both for advice.
Hi John,
May be this site helps you: http://www.geocities.com/marcboncz/citroen/. Under 'maintenance' there is a article about the fuel smell Marc Boncz experienced and what the solution to it was.
Regards,
Freek
May be this site helps you: http://www.geocities.com/marcboncz/citroen/. Under 'maintenance' there is a article about the fuel smell Marc Boncz experienced and what the solution to it was.
Regards,
Freek
Thanks for that - useful site and I hadn't come across it.freek wrote:Hi John,
May be this site helps you: http://www.geocities.com/marcboncz/citroen/. Under 'maintenance' there is a article about the fuel smell Marc Boncz experienced and what the solution to it was.
Regards,
Freek
Regards
John