First of all, I want to apologize if I do not respect the common way to use of this forum. Maybe I had to present myself or my car before. Also, I precise that I am French, and I speak English at the best of my abilities, so maybe I will not be clear at all steps, but with the pictures, I hope it will precise my comments.

I just write this hoping that it can help somebody around the world, who owns a Jaguar XJ40 (maybe this solution does also works with the X300, which is similar to the XJ40), and who despairs because of a rain water leak inside the car.

Many times I obtained help for my cars (Saab, Volvo, TVR) via many different forums, and I never posted a sentence inside one of them, because the answers I needed where already written.

Today, it’s my turn because I laboriously searched a solution for my problem, but I never found the solution on the internet. However, I found many people asking with a similar problem than the one I had, and no one replied with a solution. Maybe, it’s not solved until now... Consequently, after finding the solution for my car after many days of observation and research on it, I will explain here all the way to solve the problem.

Also, I precise that I am a beginner in mechanic. Actually, I am normally just able to change a wheel, to replace cabin filters and air filters, and spark plugs on engines where they are easy to change. For example, I replaced one time a bumper in a Volvo S60, and it took me a complete day.


THE PROBLEM:

During one year, I had an important rain water leak inside my Jaguar XJ40 4,0 Sovereign made in August 1993. The car only has 72,000 miles (115000km). It’s a left hand drive car, because I am French.



SYMPTOMS OF THE PROBLEM:

I identified there was a problem because the car had more and more mist on the inside face of the windscreen just after switching off the engine. It was very strange because the climate control system is very efficient in the XJ40 to demist.

Consequently, I removed the lambswool and the wool carpets of the car. Under that, there is insulation black foam mats which were totally flooded inside my car. I am lucky because the water level was just under the electronic systems driving the front electric seats. Half a inch higher, the electronics were also flooded.

I removed the insulation black foam mats from the floor and I drained them. I was able to fill a full basin of water with the rain water I had in the car. Then, I dried the metal floor of the car.

I have to precise that : To remove the insulation black foam from the floor of the driver and passenger places, I had to cut it behind the pedals and along the transmission tunnel, because these foam parts are very big and are fixed behind the dashboard (Saint Jaguar, Mea Culpa to have destroyed some parts of your beautiful creation!). Be careful when cutting these parts because there is some electrical wires behind them (For example to go to the kick-down sensor behind the throttle pedal)

Then I let the car with moisture absorbers inside it to dry it during many days.

When most of the foams where dried, I did some trials to identify from where the water was entering in the car.

I saw that the foam behind the pedals and next to the climate control system where always wet. More precisely this foam is situated on the partition separating the engine from the passengers compartment and on the transmission tunnel.

So I searched to identify the different possibilities of the cause of the problem :

- A clogged duckbill : The duckbill is a flexible rubber hose, situated under the wiper motor, in the engine compartment. The duckbill drains the water which falls on the windscreen, then goes under the windscreen finisher, in the compartment where there is the wiper mechanism and finally fall from the duckbill on the floor under the car. My duckbill was perfectly clean and has been split on both of its flat sides by the previous owner of the car to be sure that it will never clog.

- The climate control drains are clogged : There is one drain in each side of the transmission tunnel, next to the driver and passenger foot place. After many research and trials, the ones in my car were clean, and all the climate control system is perfectly running.

- The drains of the opening sunroof clogged : My car doesn’t have an electric opening sunroof, so this cannot be the cause of my problem.

- An other cause, unidentified and without solution until now… -> It was my case !

So I worked many hours to identify the cause of the problem, and I found it :

The entry of the rainwater inside the car was by a foam seal which is situated around the two copper hoses of hot water going from the engine to the radiator located inside the climate control system. From the engine bay, it’s possible to see the foam seal around the two copper hoses entering in the passengers compartment.

Normally, water should not enter in the engine compartment, not more in the passengers compartment.

But in my case, the leak was organized as following :

When it’s raining, the water fall on the windscreen. Then, the water trickles inside the compartment under the plastic finisher supporting the two windscreen washer jets, where there is the wiper mechanism. Then, the water should normally goes form the compartment to the duckbill and fall onto the floor under the car.

However, the duckbill and the wiper motor are united on the same plastic plate (a black plastic plate). This plastic plate is fixed to the compartment which collects the rainwater under the windscreen. In order for the water to go properly from the compartment under the windscreen to the duckbill, the plastic plate supporting the wiper motor and the duckbill must be placed in a sealed manner against the compartment under the windscreen.

In my car, and I suppose because the age of the car, the plastic aging and the heat given by the feline living under the bonnet, the plastic plate supporting the wiper motor has been deformed. So the rainwater flows from the compartment collecting the rainwater at the bottom of the windscreen, between the plastic plate supporting the wiper motor and the bulkhead separating the engine bay from the passengers compartment.

And then the water continued to flow vertically, and more precisely on the sealing foam situated around the two copper hoses used for the climate control heating. This foam isn’t waterproof and absorbs the water, which goes by this way inside the car. Then the water dispersed in all the black insulation foam which covers the floor of the car. Naturally, water was stored in the lower place of the cockpit, the floor foam mats.

Beyond this point, the solution I used to solve the problem.



SOME THINGS TO KNOW BEFORE TO BEGIN

Degree of difficulty : medium

Duration : 6 to 8 hours for a beginner mechanic (like me!). It’s better to do it during two consecutive days in order to let the sticky gasket paste dry.

TOOLS NEEDED:

- Pipe wrench set

- Torx key set

- Rigid steel wire

- Medium size flat screwdriver

- Jeremy Clarkson's favorite tool (a hammer!)

- Possibly a small wired camera to preview the working zone

MATERIALS NEEDED:

- Aluminum corner profile (sides : 0,75 inch ; length 4 inch) (sides 15mm ; length 100mm)

- Gasket paste (Bardahl 1C - Easy gasket black is the one I used)

- Touch-up paint matching to the car’s color

- Windscreen wiper motor seal (DBC2932)


STEP 1: DISMANTLE OF THE WINDSCREEN FINISHER

First of all, open the bonnet of the car.

The first thing to do is to dismantle the wiper arm. For that, with a pipe wrench, loosen the nut located on the rotation axle of the windscreen wiper arm. To access to the nut, you should open the small hood (part n°5 on the following picture) by a rotational movement. Then, you can remove the wiper arm.



Unscrew the five Torx screws located on the windscreen finisher (part n°1 on the following picture).

This is the part, large as the car, supporting the windscreen washer jets.

To remove the windscreen finisher, you will need to disconnect the windshield washer hoses located under the washer jets. Also, for the vehicles with the equipment, you will have to unplug the electrical sockets of the heated windshield water jets.

To help yourself in this job, you can remove the two water deflectors (parts n°5 on the following picture). For that, place one of your fingers in the hole placed the more in the centre of the car, and raise up the water deflector gently. They are simply cliped.

Please be careful during this step with all the plastic parts. Most of the times they are old as the car so they are very brittle.



To finish this step, with a big pipe wrench, loosen the big nut which maintains the wiper arm axle to the windshield bay. Thereby, the windscreen wiper mechanism is no more linked to the windscreen bay.

Note well : If you find rust in the compartment at the bottom on the windscreen which collects the rain water, it’s a possibility that the duckbill is completely clogged and the rainwater stays there for a long time instead of going out of there. In this case, you must find the solution and repair all the area as soon as possible. Otherwise your beautiful British car will quickly turn in a pile of rust… A sad idea isn’t it?



STEP 2: REMOVAL OF THE WINDSCREEN WIPER MOTOR

First of all, disconnect the electric socket of the wiper motor and remove the duckbill. The duckbill is the flexible rubber hose situated under the wiper motor (part n°2 in the following picture). With one hand, it’s pretty easy to remove it by pulling it in direction of the ground. In my car, the duckbill looks like the suction nozzle of a hoover, and is longer than the duckbill showed in the picture. Also, there was no clamp (part n°3 in the following picture) to retain it in my car, but one is shown in the picture. Maybe the clamp was lost by the previous owner of my car.

During this step, it’s a good idea to take time to completely clean the duckbill.

To remove the windscreen wiper motor, use a pipe wrench to unscrew the three hex head screws which are situated at the top of the black plastic plate supporting the wiper motor.

At the bottom of the plastic plate supporting the wiper motor, there is three sliding metal clips. To open the clips, use the small diameter rigid metal wire by twisting one of the end of the wire in the form of a U. Then, you can place the twisted end of the steel wire in one of the clips and slide horizontally to unlock the clip.

I have to precise that the center clip and the left clip (located the more at the center of the car) will be opened by sliding them horizontally in direction of the center of the car. The clip located in the right side of the plastic wiper motor support (on the driver's side) will be opened by sliding it horizontally in direction of the driver's side of the car.

This step takes time because the left and centre clips are not fairly visible. I had to take time to locate them with my fingers, and then carefully place the twisted steel wire before sliding the clip while caring to not get caught in or destroy the electrical wirings that are located in the same area.

After having unlocked the three sliding clips, you can remove the whole wiper motor assembly. You will have to pull the assembly towards the front of the car while rotating it in order to disengage the wiper arm axle from its location. Maybe it’s a good idea to be two people, one on each side of the car, to do this step easier.

When the wiper motor assembly is out of the car, you can clean it, especially the surface where the water flows to go to the duckbill. And also, you can replace the foam gasket (DBC2932)




The following picture shows the foam which is around the two heating hoses after the wiper motor removal. This seal is fixed inside of the passengers compartment, all the water going on its surface in the engine compartment will be absorbed inside the foam and then will flows inside the passengers compartment.



In this picture we can also see that the little thing on which slides the clip retaining the wiper motor support is covered by rust. This is not normal because it should never be in contact with water. And in my case, the two other things on which slide the two other clips were like new. No rust onto them.

So I decided to cover these things with a solution to protect them from corrosion.



STEP 3: THE SOLUTION

I assumed that the plastic plate supporting the wiper motor was definitely deformed. So I deduced that the renewal of the wiper motor gasket will not be sufficient to solve the leak problem. Consequently I decided to add a second way to keep the rainwater far away from the absorbing foam located around the heating copper hoses.

This second way is like a gutter, which deflects the water leaking from the wiper motor support to the floor under the car.

For that, I cut an aluminum corner profile whose sides measure 0,75 inch (about 15mm) with a length of 4 inch (about 100mm).

I cut the corner profile in one side for it to match to the curved opening by which the wiper mechanism enters the compartment which collects the rainwater at the bottom of the windscreen.

Also, the side of the corner profile which has been cut, has also been drilled with small holes of 0,1 inch diameter (about 3mm diameter). While entering in the holes, the gasket will make the repair stronger.

Then I glued it to the car with the gasket paste. I used enough paste to cover all the holes drilled in the corner profile with that in order to fix it securely to the car.

After the corner profile has been fixed to the car, the result looks like that :




Also, a bead of gasket paste has been place to the ledge of the corner profile to make it look like a gutter

As well, directly below the end of the gutter where the leak water falls, I realized a vertical bead of gasket so that the water leak cannot return laterally under the gutter to go onto the absorber foam seal of the heater hoses.

Looking back on my thinking, and more than this solution, I should have covered all the absorber foam seal of the heater hoses with this gasket paste. In fact, this product is waterproof and adapted to temperatures going to 260°C (500°F), so it will support the hot temperature of the water hoses. Moreover it remains flexible at it ages. I think it’s definitely an improvement to do.

After this step, the best is certainly to let the gasket dry during one night.

Then, you can paint all the repair, including the gasket, with the touch-up paint. After that, the repair will be fairly invisible.



STEP 4: REASSEMBLY


After finishing all the previous step, you can reassemble the car’s parts, in the reverse order of the disassembly operations.

To lock the sliding clips at the bottom of the wiper motor support, you can use a little hammer to gently knock a flat screwdriver which will be placed on the sliding clips. You can also put oil onto the sliding clips to help them to slide properly.

Normally after that your old Jag’ is waterproof as it should be. So you can reinstall all the foam mats and the wool carpets inside it, but only after all is completely dried. In my case the car needed three sunny weeks to be ready.

After that, you just have to drive it as it should be : as the most fabulous car ever made all over the world… Thank you very much Sir William Lyons !

 

BEST FIRST POST EVER!!!! Great job!!!

 

There can sometimes be another point of entry, the electrical grommet where the harness enters at the side of the footwell, behind the fusebox.
Depending on whether the car is LHD or RHD and road camber when parked. Either side can cause the issue.

See my solution:
https://www.jaguarforums.com/forum/x...carpet-174425/

Larry

 

Hello Ju44,

Welcome to the Jaguar Forums! It's great to have you with us!

Thank you for your detailed post on how you resolved your water ingress problem. It will be very helpful to others.

While you may be inexperienced as a mechanic, you obviously have invested the time to learn about your car and you have the ingenuity often required to keep our old Jaguars performing properly. I would highly recommend that you invest in a good quality set of sockets so you don't have to use a pipe wrench on any part of your car that you intend to re-use!

Also, please visit the New Member Area - Intro a MUST and post a required introduction so we can learn something about you and your Jaguar and give you a proper welcome.

Cheers,

Don