94 Vanden Plas ~
Anyone have a mysterious problem with driver side floor mat soaked after heavy rainfall combined with serious fogging of windows (no garage) ? Happens every spring / winter. Glad that summers arrived to evaporate moisture coming in from ?? Body drainage tubes cleared without successful results -- even had complete dash removed & body seams sealed -- helped 50%. Not concerned as much this time of year but then again who's to fix a leaking roof when the sun's shining. Suggestions for fix appreciated.

 

Shaemus,

If your parking outside (me too), I would be suspicious cavity located under the finish piece that runs the width of the windshield and covers the wiper motor.

See this page: (item 1)

Windscreen Finisher-Lower - Parts For XJ6 & XJ12 from (V)667829 to (V)708757 | Jaguar Classic Parts UK

The finish piece is easy to remove and the cavity has most likely filled with debris, thus plugging up the infamous "duckbill" drain tube, accessible via the engine compartment, located underside of wiper motor housing. The duckbill drain clogs with the debris and needs to be cleaned on a consistent basis.

It has happened to me, I'm in Mobile, AL and we get rain! Lots of it. If I have been undisciplined in keeping this area cleaned out, the debris will cause a dam effect and the rain water level will rise inside of this cavity which also provided the venting for your AC blowers/fans.

So when the water rises real fast there is no where for it to go but through the duct work for the blowers and into your blowers, which will eventually leak out the water....onto your floor mats. As you can imagine, this isn't good for the blowers either.

Regarding the foggy windscreen, I would suspect your demister flaps are failing, one or maybe both. They are either not holding vacuum to keep the flaps in the closed position, or they could be failing structurally, as in pulling away from they're anchors from the inside of the dash.

If you need to use the demister/defogger during the winter, then the choices are few, which implies the need to pull the dash to do the repair. Let me know and I'll go into more detail if this is the case.

Good luck.

 

Rob .. Wow !! Really appreciate your insights. The cavity you mentioned as well as the drain tube have been thouroughly checked out by various mechanincs (And myself after been shown the location and how to clear the tube) trying to locate the problem . The windshield has also been inspected for leaks.
I believe the fogging and soaked drivers mat is definately related .. first time anyone's mentioned the demister flaps & it seems to make sense (or I'm finally hoping for a solution). The demister is a feature that I've never quite been confident as operational since purchase -- the function light comes on when It's selected but I've never seen any difference in performance. The flooding is only on drivers side .. could structural damage in the flaps be a plausable solution for both issues?

 

Shaemus,

Short answer.....no.

The demister flaps are located inside the cabin, further they are contained within the air box (dash). But, if there is water in the blower assembly and it's heated from the sitting in the sun, when you activate the blowers they may transfer the steam you reference up through the defunct demister flaps.

I believe you have two distinct issues at hand which are coincidentally occurring at the same time. One slightly related to the other, but not a direct link as in cause/effect.

Regarding the water: if your mechanics really removed the finish piece, and really cleaned out the cavity (am I sounding skeptical yet?), and really cleared the duckbill drain, how long ago was that done? They could have missed something, or were not thorough. Keep in mind, two little leaves are enough to cause blockage, coupled with a downpour, there will be a damming effect. Simply stated, the Jaguar engineers really didn't think this one out carefully.

A common cause/effect of moisture in the cabin are the evaporator drainage tubes located on either side of the climate control unit.


WOW. MIND BOMB JUST WENT OFF!!!

You need to have your heater core checked.

There may be a leak in the core, or the seals have deteriorated to allow leakage. The seals are located...... on the drivers side of the core. It just hit me that you referenced the occurrences happen in summer and winter.

Yes, the heater core is still active, even with the AC in use. The flow of water is controlled by a vacuum valve located in the engine bay on the firewall. If should have a red vacuum tube coming off the top of it. In your case, you still need to have the core and connections checked in the cabin. The vacuum valve wouldn't cause leakage in the cabin. Many owners have opted to have the vacuum valve removed and in it's place install a good old fashion manual ball valve. They open the ball valve in the late fall and close it in spring, thus controlling the flow of water to the heater core. This method actually helps with additional cooling effects in the summer.

In regard to the demister flaps and your reference to "fog or foggy". This could be condensation on the windscreen from the AC (again, failed demister flaps) or steam from the aforementioned heater core.

When the AC is activated the demister flaps should be closed, forcing air flow to the front vents. An easy way to check, without paying a mechanic, would be to remove the center wood trim piece, then remove the center vent piece. With the AC on, the center flap should be in the open position and you will be able to see beyond that flap and it should be dark, another words the demister flaps would be closed and not allow any light through. If you see light, then I would assume the demisters need repair......out comes the dash.

I still think you need to investigate the demister flaps, I think there is something amiss there. You also mentioned in your original post that you've had the dash removed before.....I wonder if they were careful when re- installing.

A word about your mechanic, don't get me wrong. I love my mechanic, but due to job layoff I had to take on repairs myself and I have made discoveries of their work that have left me....well ....disappointed. Still love the guy, but not so much his crew, thus my jaded cynicism.

Have the heater core checked. Good luck

 

Rob .. Sorry to have taken so long to respond. Thank you -- everything you've mentioned makes more sense than I've heard from any of the mechanics that've worked on my car (I've had several). I'll investigate all the possibiities you've mentioned before the next rain season & will let you know if the symptoms reoccur. ~ And, if you're ever in the PDX vicinity, I'd be more than happy to treat you to a barley pop @ the local pub !!

Thanks again.

 

Check sunroof drains, use piano wire and chase thru tubing carefully not to pierce, air can be used, but can blow tubes off pressed on mounts.

 

We had a heavy downpour on the way home from work last night and I could hear water sloshing on turns (not good). So, today I tried to look for the drain in the cavity. I took off the finisher and stared into the cavity but didn't see anything that looked like a drain hole. Does anyone have a picture of where the drain is for the cavity under the windshield?

 

I finally found the duck bill with the help of NTL1991. I was looking in the wrong place for the "duck bill!" It is attached to the drain at the bottom of the windshield wiper motor on the firewall in the engine compartment. I was looking for something inside the cavity below the windshield.



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