Facelift Sill Drainage

[mike.p.smith915]

Hi,

Can anyone confirm if the sills on a 1994 facelift XJS 4L should have open drainage gaps in the lower seam where the inner and outer sills along with the floor pan are welded together?

It looks like the outer sill has small (about 25mm) drainage channels crimped into it at intervals along it's length but on my car these have been welded over as part of earlier floor pan repairs. I need to replace sections of the floor as it has rusted away but I don't want to weld up drainage gaps if they are required. The inner and outer sills seem in good condition, it's just the floor pan that has dissolved along the seam line.

I have seen a picture of an early XJS that appears to have rubber drainage tubes within the sill gap towards the rear wheel arch but these are not present on my car.

Long story short - is it best to close off what appear to be drainage outlets that may no longer be required to stop water ingressing from underneath or leave open? Welcome your thoughts.

Regards
Mike

[PaulGover]

Can't say for '94, but my '91 facelift definitely has drains as you describe: the welded flange sits away from the inner sill leaving a few mm gap, for about an inch in length, spaced every so often along the sill. Of course, if you sill is totally watertight, there should be no need for drains! My experience is that the main source of water ingress is rust holes in the closing plate at the back of the front wheel arch. There are also some holes filled with bungs for something like mud flaps on mine; and once water gets in, you want to let it out.

At least on late cars like yours all the metal has a decent coat of zinc.

AFAIR there are also some rubber hoses; they aren't drains for the sill, I think they're vents or overflows associated with the fuel system. I'd worry if they were missing...

[mike.p.smith915]

Hi Paul,

Thank you for your feedback on this. Sound advice. I think I will leave the gaps open when I replace the floor and make sure the area is well rust proofed. As you say, its better to let the water get out again if it once gets in.

There were holes in the closing plate at the rear wheel arch end of the sill which I have fixed now. I'm expecting similar at the front when I get there. I started work on the car at the rear bumper and have been working forward. Some parts of the underside look as good as new and some have just dissolved. I guess the zinc plating has been compromised in places over the years and that's where the rot has set in (the car has done 200,000 miles in all weathers so it's probably not surprising).

I will double check on the fuel drains to be sure. The tank is out of the vehicle at the moment and I can't remember where the drain from the fuel filler went too. It definitely didn't drain into the sill area but you have got me thinking now as to where it did drain.

Thanks again for your guidance on this. Greatly appreciated.

Kind regards
Mike