I own a 93 XJS Coupe(Kingfisher Blue) and had similar problems. The leaks were the same in both areas you have mentioned. The car had a total strip down repaint in 2015. There was no evidence of windscreen post and frame rust. The culprit was the worn windscreen glass and rubber seal. The windscreen had some minor worn cracks hidden underneath the rubber window seal.. The seal had separated from the bottom of the glass just enough to create a very tiny opening. There are no drain holes under the seal. The water drains to the side. If your seal has some form of caulking/sealant under the seal, then the water coming down the glass has no where to go but through the tiny opening and then the interior. Grant nailed it in his post. I have an extra windscreen rubber seal. The shop that did the work had ordered a seal for a 94. In 1993, the windscreen seal was a one off. I finally located one in London from a breaker yard. I don't know if the extra seal will fit your XJS, but a vin check would resolve the issue.

 

now I apologize for not taking those pictures last night when I got home...
but what happen to mine was the air plenum drain were fully clogged
this left the rain water only one path to ground from the windshield wipers/aircond. intake plenum to the ground. That path would be into the air-conditioning system and any way down from there.... which in a turn would throw the water to the out side and come down the path you showed in your illustration... (wife unhappy!)
removing the plenum drain was a lot easier that I ever imagined... and clearing it even easier...
it is now part of my quarterly routine...

 

MHF25 - Thanks for your comments. I'll admit, I'm more suspicious of the windscreen seal that the A pillar drain, seeing as there doesn't appear to any blockage in the drain (then again, the leak is [so far] very minor (though I want to keep it from getting major).

Jonathan-W No need to apologize at all. I'll check the air plenum drain, but found a minor problem - I can't get the RH wiper off (haven't tried LH). The nut undoes very easily, but the wiper itself won't budge. Is this just a case of some penetrating oil (like CRC) or is there a step I'm missing? My ROM only says "undo nut and remove".
Come to think of it, if the wiper motors are attached to the grill, perhaps I don't need to remove the wipers at all. The ROM says I have to remove them to renew the plenum chamber finisher, but if I just want to poke around inside....
Anyway, in another thread Doug mentions pouring water inside and seeing if water runs out behind the front wheels. I poured water in earlier, but the ground was already wet from other water tests, so this is the first place to start....

 

Well, the plenum drains appear fine. I poured about 2 litres of water into the plenum, heard some sounds of trickling water, and this appeared under the car:


There is something that I would like confirmed, if possible. This gap in the seal. I remember reading it was actually left like that as a drain, but if not, if the seal has shrunk and pulled apart, it's a potential culprit.


I don't know what's lurking under the brightwork yet, but apart from a few rust-coated bolts under the bumpers, this is the only body rust I have been able to find:

That will need attention sooner rather than later, too....

 

Hi SDSD The photo of the seal is an interesting one and is quite different to my one.


On the full facelift cars the windscreens are bonded in, so this seal is more like a cover that goes over the top of the bonded one. I am less familiar with the earlier cars but, if it is like the full facelift cars, it is the seal underneath it that needs to be checked. Again not an easy job without removing either chromes from windscreen surround or rubber seal that sits at the very front of the dash.


As this is an earlier car to mine, please feel free to use or discard my comments as they may not be 100% accurate for your model. Hopefully others more knowledgeable on your specific model year will chip in.


Rob


P.s attached is a photo of my car with seal partially removed and you can see the bonded in screen + the top of the A pillar filled in.

 

Thanks very much for the pic, Rob. I looked up my ROM to see if it mentioned anything in the supplement about when the windscreen glass moved to being bonded, but it wasn't so much as mentioned. Clearly you're not meant to replace it.... However, while the early facelifts do share some things with the pre-facelifts, the glass is the same between yours and mine I would assume, so I assume the attachment method is the same. Except KWE do note that the second-gen facelifters, like yours, are more prone to it, so clearly something changed somewhere.

Gave the car a wash today using a pressure hose - though I kept the hose as far away from the body as practical - and no leaks, so it clearly needs a fair bit of water and/or over a sustained period.

 

the air Plenum drains are accessed in the engine compartment ... no need to remove the windshield wipers or the Plenum cover... they attack to the plenum and run down either side and then out.. the ones on my car have metal tubes in the center and are shinny the 90 degree kink before the metal pipe is where mine clogged up ...

but like you said that is not likely your problem...
sever storms here today I will check my interior after they pass for water ingress...

 

That is a bonded windscreen, the seal is between the back of the window and the metal lip, the gap in the picture is only the trim molding.

All Jaguar made convertibles had bonded screens and I believe the all Facelift coupe's had bonded screens.

If it's leaking it will need to be cut out and re-fitted.

 

Thanks, Jonathan and Warren. So I guess there wouldn't be any problems putting silicone sealant or something just to close up that gap.
I do hope it's not the windscreen leaking, however: cutting it out and refitting it sounds like a major operation.

 

I would not silicone up the gap, if you do it could cause water to get trapped under and cause rust around the window. Never use regular silicone on a car it will cause the metal to rust, you must use a neutral cure silicone.

Cutting the window out is not a major job but one best left for a professional, a wire is used to cut the silicone bond behind the screen then the screen is re-fitted with a polyurethane sealant.

 

Ah. Okay, I'll leave it then. Thanks for the warning. Looking at the photo, I'm wondering if it shows signs of having pulled apart as the rubber shrank slightly with age. I would imagine that if that gap is the source of the leak, it would be a pretty heavy leak, but then again, when the car's parked, the wiper blocks most of the water, and in motion, the wipers would keep the glass relatively clear. Might just put some water down there and test it....

I definitely wouldn't consider cutting my windscreen out myself, don't worry! Absolute disaster waiting to happen. I've seen some other threads on the forum that talk about how it's done, though before that I would like to try and determine if it is the windscreen seal at fault.

 

SomeDay,
from the pictures it is not the windscreen itself but the recess around the windscreen that gets the rust holes and while the windscreen can still be completely sealed the holes in the bodywork around the windscreen but under the crome allow the ingress of water

 

The second stage will be to start removing chrome, which I believe involves removing rivets, which will need to be replaced with screws I guess.

The first stage, which I am carrying out now, is to seal off parts of the general area with plastic packaging tape and let the car get rained on. So far I have sealed off the A pillar drain - leak still shows - and the windscreen sealant along the side it drip - again, it leaked. Now I have sealed off the entire roof chrome strip along the top, as water does get between that and the roof. I just don't know how far it gets....

 

Hello...

I'm just starting down this path myself. I've had the leak the apperars at right and/or left side of the pax compartment for a while. I thought I had it fixed when I found some rust through areas in the windshield wiper motor well, but after sealing those the leak (always during or after a good rain) is still with me.

I believe the A pillar drain on the left side is not the issue. I had it sealed off for awhile and it didn't help. I just removed the sealing material and poured some water into it, and the water exited the car near the front left headlights, which I think is what is supposed to happen.

Looking at the parts manual, I see three parts listed for the windshield...BD44231/2 (tinted or non-tinted glass), and BD44236 and BD15466/2. Is the seal a two part seal, and thus I need to order both parts?

I've got some of the trim off, and am I correct in guessing that the seal is something of a "U" arrangement, and that the second part of the seal is pushed into the "U" channel to seal everything up?

Thanks,

John
1987 XJ-S V12

 

You have a different windscreen than Some day, ours is not bonded.

My experience - I removed all the windows in mine when I repainted it and had a specialist re-install them at great expense (over $1000 just to install the glass). Guess what ALL windows except the front leaked.

So I removed the rear screen and rear side 1/4 windows and re-sealed them with polyurethane window sealant, the stuff they install bonded windows with. These windows still do not leak 5 years later, my windscreen is now leaking so I will be removing it and re-installing with PU sealant.

The windscreen leak has water running down the A pillar on the passengers side.

 

Hi everybody
I have an 1987 xjs and after a heavy rain the other day the front floor mats were soaked.I checked around the windshield an all was fine.The wipers were not working and when I disassembled the motor it was full of water. The cavity that holds the wiper motor is also the fresh air intake.In the cavity are two drains that were both blocked. Poor design!! They start at 1 1/4 through a contorted twist then into 3/4 inch tube and finally a 90 degree bend out through fender.They were both plugged.Once cleaned the problem was solved.
John

 

I dislocated my shoulder yesterday, so during the healing period I'll have time to plan this out properly.

Since I've got all the trim off, I'm tempted to just replace the entire seal and be done with the entire issue (assuming that is where the leak is coming from, of course).

Is this something I should attempt myself? No point it doing it if it's just going to leak afterwards, but from what I've read those that have had this done "professionally" often have leaks afterwards.

Warrjon, did you just re-seal yours, or did you replace the seal?

Mountaineer, I went through that too. Found to good-sized rust holes in the bottom of the wiper motor bay. I was delighted because I (falsely) assumed these were the source of the leak and would be easy to fix. They were easy to fix, but were not the source of the leak :-(

John
1987 XJ-S V12

 

I replaced back and front rubbers. I would not re-seal the window without a new rubber. When I re-do my front screen I will be replacing the rubber again.

Hope the shoulder gets better quickly...........