My Fix for Pluriels leaking water into the boot.

[Bertilak]

This is my opinion, as a mechanical engineer, on why our Pluriel leaks into it’s boot space. It is based on a sample of one, but appears correct.
There doesn't seem to be much on C3's on here though the net seems full of people wanting this info to decrying ther Cit's. So I thought I should post it...

Design fault: the outer plastic cover at the bottom of the rear hatch is sealed with a very viscous, non- setting mastic. At the sides this cover only touches the inner piece along it’s edge, which then relies on the sticky mastic to provide a perfect join. Unfortunately this seal is critical, as above it is a crevice which allows rain coming off the glass, or the slider tracks either side of the glass, to drain sideways.
On our Pluriel the mastic clearly had not sealed adequately, as there was water in the chamber inside it, which eventually gets into the boot.

My fix: strip and rebuild using black bathroom silicone sealer. This is much less viscous and allows better seating., and better sealing if not fully seated.
It may be more problematic to remove should the situation ever arise though.
• Remove plastic cover along bottom of hatch on the inside. 8 torx screws.
Remove 4 nuts (8mm hex) behind that cover that hold on outer cover.
• Working from each end carefully and slowly prise outer cover off, you are easing away the mastic bond here. You’ll probably want a few decent sized flat screwdrivers. Note the cover is very weak in the middle due to the hole for rubber cover for the opening button.
• Clean the mastic from the upper edge and ends of the outer cover, and on the inner moulding where it mates. This is a horrible job best done with lots of small cotton rags (old denim worked well). There’s no need to remove all the mastic (you won’t want to) . If you’ve ever got it on your hands when closing the bootlid (like we did) you could lean it off the bottom edge too.
• There is also a foam rubber piece at each end that would be better for cleaning and siliconing, this is possibly an additional leak path.
• When ready, build up a good thickness of silicone to seat the cover in, especially on the inside at the ends. Stick the foam pieces in with a generous siliconing. Also put a small run of silicon along the width of the bottom of the glass.
• Then assemble the outer cover onto the silicone, and hold on with the 4 nuts. Press down to bed into the silicone and what’ s left of the mastic. I pulled a piece of thin card through the horizontal gap between the cover and the side frame of the glass, to ensure this drain crevice is still clear.
• Then apply a bead of silicone between the bottom edge of the glass and the cove in the normal bathroom fashion. (use tape to restrict smear, then mould with finger lubricated with washing-up water).
Result: No leaks, OE look finish, like it should have left the factory!

Possible alternative, simpler method: (untried)
It may be possible to simply pump the end crevice at the bottom of the side bar full of silicone, making sure it links the side bar to Cover, and the glass.
This would mean the cover does not have to be removed, but water may collect on the cover at the bottom of the glass, especially if parked facing downhill. The sprung cover for the roof slider track may need prising (one edge first) out at it’s bottom end to ensure silicone does not build up behind it, and possibly snipping by a few mm if the silicone stops it squashing downward in action.

[wheeler]

Just to add. the early models had the rear badge trim fitted on with hard setting sealer, the problem was this cased the trims to split as it was to rigid, Citroen modifed them to fit with soft selaer which stopped the trim breaking. both versions still leaked water in.

[Lighty]

Interesting info Guys