Source of Water Ingress Located?

Well, kinda. Was trapped in Superblue tonight in a parking lot at my office during a MAJOR thunderstorm, waiting for things to subside before making a dash for it. :grimacing: While sitting there in the darkness, I could feel drops of cold water dripping slowly onto the top of my bare left ankle. :open_mouth: I decided then and there I was going to find out what the source was of that water leak that always causes my driver’s side carpet floor mat to end up wet and a shallow puddle of water in the forward area of the rubber mat on top of it after rainstorms.

I took out my little flashlight to begin my quest and shined it onto the front of the dash, where I could see water rapidly dripping down from the bottom edge of the dash panel onto the top edge of the knee bolster panel just below the area of the instrumental panel light dimmer knob and hazard light switch panel (and map light). From there the water ran straight down the front of the knee bolster panel (keep in mind that the bolster panel is angled inward slightly toward the driver instead of being mounted perfectly vertical), dripping off the bottom edge of same and from there onto the floor mat below. Since the turnbuckle that secures the knee bolster panel along the left edge is broken off on Superblue, I was able to go ahead and lower the bolster panel w/o having to open the door and unfasten (i.e. twist) it. Peering into the darkness behind it with my flashlight I could not see any water dripping or even any sign of dampness in there (thankfully, considering all the wiring, fuses, etc. located in that cavity! :relieved:). I then raised the bolster panel back into place.

Although I am still not able to see precisely where the water is getting inside the car from, my theory now is that from wherever it is coming it then runs down along the bottom edge (from left to right) of the dash panel until it gets to that area mentioned above, at which time it then drips downward onto the top edge of the knee bolster panel, and then down from there, eventually onto the floor mat, as described. :thinking:

I did at one point, although the rain was still coming down like crazy, quickly open the door and stick my head out, pointing my flashlight at the forward door sill. It seemed like I could see water dripping and falling straight down from a small “rail” located at about the height of the side-view mirror on the frame.

Anyone’s thoughts on this issue, now? :confused:

I have thought of trying a couple of things (one or the other) to finally rule in or out that it is the door seal having been worn down with 90K+ miles of use plus 15+ years. One is to try using some of that black “Flex Seal” stuff to thicken the door seal in the area where it is compressed when the door is closed to the forward side. Alternatively, to take another old door seal and, cutting out a matching “patch” piece from it, glue it to its corresponding area on my current seal, in the same area mentioned above. This would make a “double thick” seal, which, both being old seals, might approximate the thickness of one new seal. If either of these measures stops the leak, then we know it’s time for door seal replacement. If not, then the search goes on … :confounded:

Hows the windscreen seal?

When I removed the front windshield of my wife’s 1990 XJ-S convertible in preparation for it’s repaint in 2014, I discovered that the seal had failed over significant sections at the bottom of the glass. That car rarely experiences any rain but prior to the repaint sometimes the carpets in the footwell got damp after I washed the car. The gaps at the bottom of the windshield in that car would have definitely let in water. Perhaps you should take your car to a windshield expert to see what they think about your windshield seal. Although I removed the original windshield myself I had a new replacement windshield installed professionally after the repaint. The original one had a star right in front of the driver and needed replacement.


I don’t think one can find replacement windscreen anymore. I tried about a year ago to find one for my 95 coupe and it was nigh impossible. I was gonna replace the one in it since it has 25years of road abrasion. I would have to think really hard before removing the one that is installed.

Hmmmm … I guess it would be possible to r/r just the seal and find out, but I thought by the time the face-lifts came along Jag had corrected the leaking issue with the windscreen seal (?) In fact, it supposedly has a different design and “locking” mechanism than the pre face-lifts utilized. :confused: So is everyone saying there is no way it could be the door seal now or a blocked door drain?

I’m wondering if there is a way to test the windscreen seal. Maybe, while at the car wash, use duct tape to seal up the gap between the door and the body along the top and front side, then spray the hose at close range and high pressure along the bottom of the windscreen, going back and forth slowly, for a substantial length of time. (?) :thinking:

I know that mine was getting water in the floors. I think I got it to stop, at least for the majority. It was hit or miss depending on how the rain was. I replaced the door seals and still had a little coming in there, so I actually adjusted the back of the door in a hair and that helped a little too. Of course then one morning after it had rained for 3 days straight I went out and there was an inch in the driver’s floor! Argh! I cleaned it out again and since it was to be raining heavy again, I decided to sit inside and look and listen. I was sitting for a minute while it was dumping it down then I heard “blip blip blip blip” I took my flashlight, yes it was dark by then, and started looking around. Long story short, my rear window was dripping heavily on the left and some on the right! I put a tarp over it and went to bed. It rained that way for a couple of days, but when I got in, the floor was dry! I ended up just running a bead of clear urethane around the window under the seal for now. So far so good!

Did I hear you right, that new windscreens aren’t available?

I have a little crack in my 88 windscreen, upper left, that one day I’d like to replace. Are used windscreens the only source now? Wow.

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I’ve read that too. I meant to ask the local Safelite when I had my xk8s done but forgot.

I was going to buy one from Safelite. Had it all scheduled up using their online interface. 2 days later they called and told me they couldn’t obtain a windshield for me.
I think one of supply houses had one for 1600.00.
And I think the coupe versus a convertible factored into the equation.
At any rate, good luck fellas.

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Saw some motortrend car episode, where they needed a windshield for a custom chop. Went to a windshield shop in California, said what they needed. Owner had several hundred or thousand inventory, pulled one for a chevy and cut it to fit exact. Way cool, didn’t know you could cut them.

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That’s who I’d recommend, and get it done, a.s.a.p., before it gets worse. One thing I wish someone would suggest to them is to come up with a resurfacing procedure they can use on our older windshields, to take all the pitting and such minor imperfections out of them that have accumulated over the miles. My body shop guy used to own a shop in Saudi Arabia before he came to the U.S., and he said that, due to the sand storms there, they used such a procedure in that part of the world. They apply some kind of (paste?) to the windshield and, using a buffer (or orbital sander?) they are able to polish it out, akin to wet sanding the paintwork, so that it looks like new on the outside. :cool: He said though he has not seen anyone using this same technique here in the U.S. Wish someone would … :pray:

I don’t understand - the leak was from your REAR window, and yet it was puddling in the FRONT floorboard? :confused:

Indeed. Basically the water came from the rear window, dripped onto the rear deck, ran down into the rear storage box (my 93 convertible doesn’t have the rear seat) and from there “flowed” into the floorboard running forward into the lowest spot, ie the floor in front of the driver’s seat. I only got a little in the passenger side, so I’m wondering if it may have to do with the way the floor pan was stamped. Believe me, when I covered the rear window with a tarp and then the floor stayed dry, I was surprised too! Like I said, as a semi temp/perm fix I popped the seal and used clear urethane all the way around then refitted the seal. No more leaks and the floors stay dry.

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I sometimes get confused between things I’ve done on the XJ40 I used to own versus the XJS I currently own. An obvious source of water leaks is the air vent cavity on the cowl outside the center base of the windscreen (houses the W/S wiper motor).

In my '89 XJ40 (I think) that air vent cavity/plenum had nipples in the firewall at each end/side that routed rainwater out through the firewall & forward several feet, via rubber fittings on long straight metal tubes (about 3/4" dia) that sloped gently forward to rubber fittings & nipples on each of the two inner fenders, dumping the rainwater out into the wheel wells. When those drain tubes were blocked by decayed leaves, the water level in the cavity rose and spilled into the air passages and I got wet feet. The air passages also have water drains (going to tubes near the transmission, I think), but those can only handle minor water leaks. I know I cleaned out those leaf-plugged tubes several times with water pressure from a garden hose (but, again, I suspect that may have been on my XJ40… its dark & raining presently so I’m not gonna go look at my XJS right now) …anyone know where the equivalent wiper cavity drains are in the XJS?

Also, check these prior posts:
[xj-s] It STILL leaks water!
[xj-s] Wet from the wiper box and "leak-map" for XJ-S
[xj-s] Leaks Into Footwells
[xj-s] Water Leaks Into Footwells
[xj-s] Water in drivers footwell information for all
[xj-s] 2 Hoses?
[xj-s] rain leak

Oh boy - yes those rubber “duckbill” drain hoses … What a problem! :angry:

No, fortunately Jag forewent the duckbill drains on the XJSes, at least on the face-lifts. Our plenum box does have two large (2" diam.?) short rubber drains hoses on either side of the base of the box, which drain water out of the box onto the ground in front of it (I guess Jag finally realized wheel well drains were NOT a good idea - as far as starting rust there! :grimacing: ). I did check both these hoses by quickly dumping a milk gallon jug or two full of water into the box on either side, and they are completely clear, so that’s not the source of the leak … :disappointed:

My 93 xjs does indeed have the two pipes/rubber hoses that empty into the front wheel arch, and yes mine were clogged, but I didn’t get water from there as I unclogged them soon after getting the car. My original thought when I found they were clogged was “Yay! No more water in the floorboards!” Then the next time it rained I had an inch or so.

Well dang, now I’m going to have to take a second look at mine, unless Jag made the change from wheel arch drainage to front in '94 MY. :confused:

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Hi Wayne,

The XJS has similar drains. Easy to get to by removing the intake vent at the base of windshield.

Geoff Green

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