www.jec.org.uk

My V12 Coupe usually lives under cover but it was left out in the rain the other day and I found quite a bit of water in the passenger footwell. I went through all the usual causes and came up blank. Things I checked were

1. The windscreen was removed and replaced (and some corrosion fixed) when the car was restored a couple of years ago. Perhaps that wasn't sealed properly? So I put slightly diluted washing up liquid around the screen edges and pressurised the car using an air line and looked for bubbles of escaping air around the screen. There were none.

2. I checked the roof drains down the A pillar. All was running as it should with no blockages. I know the metalwork is intact as it was repaired during the restoration.

3. I checked the door seals. Whilst not brilliant (which XJS is?) they were holding.

4. I checked the plenum chamber and the drains were clear and doing their job.

5. I checked the aircon drain tubes and they were not blocked

So I was stumped! I decided to strip out the footwell carpets etc and the dusted the area with talcum powder and left the car out to see what happened. It did strike me as bizarre that I was leaving my car out in the rain because it leaked!

What I found was about half an inch of water in the footwell and a tell-tale streak through the talc from the top of the sill where it meets the A pillar. What I couldn't see was where that water was coming from so I dug around inside the lower box section of the A pillar and found a drain tube. This was the drain for the sunroof and it is supposed to go through into the sill and drain through a slot in the bottom. The end of mine was on top of the sill and the water was running over the top and into the footwell - not a great idea as it was going via the engine ECU which is bolted to the side of the footwell!,
I've now put the drain tube back through the sill and checked that it drains as it should and left the car out in the rain yesterday.
No leaks last night but haven't checked it yet today!

good find

i too have the sunroof in my Coupé , and during the restoration was surprised to see how ' DIY ' the installation of the drain tubes were , lol ,and the fact they ran directly into the unprotected sill area's ,

the rear ones are even worse, they run down behind the rear side window vent, into the body behind the rear speakers and into the sill ,

i am still on the hunt for new sunroof seals , they are different for metal and glass roofs ,

BB

We did make sure that we put plenty of waxoyl in the sill but I've now also made sure that the drain slots in the sills are clear or the sunroof drains will fill the sills!
Regards
David

Good news is that, despite heavy rain yesterday and overnight, there is no water in the car today at all - dry as a bone!!
Picture below shows the footwell with the drain tube sticking out. I've now put it back inside the A pillar and made sure that its poked well inside the sill and draining properly.
As you can see, I now have some talc to clean up and some rust prevention to do!

Full marks for your detective work. Glad mine has a roof, although still naughty ways water can get where it should not be.

David,

Glad it's resolved. I know of one owner who went further to avoid the water draining into the sill at all. He extended the drain tube to just exit through a drilled and grommeted hole on the inside vertical wall of the sill.

Paul

Paul,
I like the sound of that, truly a permanent fix.