Condensation and damp carpets

[PurpleMoonlight]

I am suffering significant condensation in my 1993 Daimler Double Six. Such that the front carpets and insulation foam underneath becomes damp. It doesn't happen to the rear carpets though.

Any ideas why this may be happening and how to combat it please?

Many thanks.

[Hooli]

Rust probably

Are you a member of XJ40.com? if not it's worth joining for the advice & experience.

Short version of their answer will be the inner wings rot behind the splash guards letting water in around the fuseboxes which soaks your carpets etc. Even clean looking cars can have rot there, it seems to be a standard feature. Bulkheads also rot at times, especially under the wiper motor as the draintube (duckbill) blocks & fills the hidden section the wiper motor lives in.

[PurpleMoonlight]

But this is happening when the car is not being used. It is parked outside.

[V8s ONLY]

Windscreen seal,sunroof drains.

[V8s ONLY]

Windscreen seal,sunroof drains.

[dbdb]

Do both front carpets get wet, or just on one side?

There are a few places XJ40s can leak; exactly where the leak is seen can help to narrow down where the water may be coming from.

Unfortunately Hooli is right – most involve rust. The most common places are:

Rust in the top corners of the plenum, just forward of the windscreen pillars. Rust here is mostly concealed under the front wing, but in some cases can be visible with the plastic plenum cover lifted/removed. It is a common spot for them to go, and even otherwise sound cars can have rust here. Luckily, it is not a complex or expensive repair, and the repair will be hidden under the wing in any event.

This is a picture of typical rust in the corner of the plenum – with the front wing removed:



The inner wing around the wiring look grommets, again concealed by the front wings is another spot. This is the place Hooli mentions; the water gets in behind the fuse boxes. Rust here is generally visible if you remove the wheelarch liner. Water can still get in here even if the car is not driven, since it cascades down fronm the plenum above.





Again, another place Hooli mentions is the bulkhead itself. Several things can cause a leak here. Most benign is a blocked plenum ‘duckbill’. On the bottom of the wiper housing is a short rubber drain tube, somewhat like a duck’s bill in shape. These are designed to let water out, but to prevent fumes from entering the car. They can block, causing the plenum cavity to fill with water. This can work its way into the cabin. Squeezing the duckbill will release the water.

However, rust is more likely to be the problem with a late XJ40 (or X300) these days. They have a weakness for bulkhead rust and even otherwise excellent cars can be affected. Earlier XJ40s with the battery under the bonnet are much less likely to have problems with the bulkhead.

They can rust along the seam between the outer and inner bulkhead. If this goes all the way through the inner skin, water can leak into the cabin.

http://www.xj40.com/viewtopic.php?f=25&t=5105



There is another possible and non-rust related cause of water in the front footwells. Blocked A/C drain pipes can cause condensate to overflow into the footwells. The pipes are routed under the carpet on teach side of the transmission tunnel.



Useful rust/restoration threads on www.xj40.com – I think you are a member there:

This is a thread about breaking a late XJ40 – but it shows a (fairly extreme) example of most of the rust the XJ40 can suffer – all in one car!

http://www.xj40.com/viewtopic.php?f=43&t=4642&...


This thread shows the construction of the inside of the bulkhead:

http://www.xj40.com/viewtopic.php?f=33&t=4160&...



http://www.xj40.com/viewtopic.php?f=25&t=5692

http://www.xj40.com/viewtopic.php?t=5223&p=685...

http://www.xj40.com/viewtopic.php?f=25&t=2653

http://www.xj40.com/viewtopic.php?f=33&t=5841

[nta16]

heater matrix??

you must remove the soundproofing material from the car to dry it out as some types can hold gallons and take days to drip dry naturally

if you leave it in the car the condensation will continue plus you'll never dry the underside of the carpets or car floor, causing rust

and if you take it out you might see a hole beneath it

[dbdb]

nta16 said:

heater matrix??

I had forgotten the heater matrix. I tend to obsess about rust!!

[nta16]

just a general possibility on some cars, I don't know on this model

hopefully if it's the matrix, it's connections or hoses OP would have noticed coolant drop and has perhaps been topping up thinking it's loss elsewhere

it's only a general possibility and could be totally wrong and you usually get the smell of the coolant, unless perhaps it's too watered down, weak or old, or there are too many other smells in the car, or the OP has a poor sense of smell like my wife when some thing is burning on the 'stove' because she's watching "Bradley"

[Flatinfourth]

I have much experience of dealing with clients cars that are not water tight!
I would buy a small dehumidifier and stand it in there to suck the car dry, its the only way to attack inaccesible water. That saves the interior and wiring, then go looking for the problem. Lots of good advicce on here, but dry the car out, and just parking it in a garage does not work!!

[PurpleMoonlight]

Another thing I can't fathom, is that the inside of the boot lid is soaking but the carpet on the bottom is dry and the spare wheel is wet under the carpet cover which is dry!!!

Edited by PurpleMoonlight on Saturday 22 March 10:23

[dbdb]

Flatinfourth said:

I have much experience of dealing with clients cars that are not water tight!
I would buy a small dehumidifier and stand it in there to suck the car dry, its the only way to attack inaccesible water. That saves the interior and wiring, then go looking for the problem. Lots of good advicce on here, but dry the car out, and just parking it in a garage does not work!!

Very good advice! The XJ40 has really thick sound insulation which will hold an amazing amount of water.

[dbdb]

PurpleMoonlight said:

Another thing I can't fathom, is that the inside of the boot lid is soaking but the carpet on the bottom is dry and the spare wheel is wet under the carpet cover which is dry!!!

Edited by PurpleMoonlight on Saturday 22 March 10:23

This is very typical of a boot leak on an XJ40. The water on the inside of the boot lid is condensation. The water will be getting in somewhere else. Water pools under the spare wheel because of the slope of the boot floor - away from the opening, towards the front of the car. Wherever it gets in, it will pool under the spare wheel.

There are several known sources for leaks in the boot of and XJ40. Fortunately, these generally don't involve rust!

A leak from the boot seal itself is rare on the XJ40 - but anything is possible. Most XJ40 boot leaks come from the following areas:

1) The lower rear trim - the black plastic trim with the chromed strip sitting between the rear lights.
This is secured by four screws. These screws are held in plastic Lokut nuts, which press into holes in the body. If they don't seal properly, water enters the box section, then seeps into the boot itself. It flows under the carpet to the low point in the boot, which is under the spare wheel. It is a common problem - my own car has suffered it. Sealing round the plastic Lokut nuts prevents water from entering and the boot will no longer leak.

2) The aerial grommet. A failed or perished aerial grommet can let water into the boot. Again, it will run under the carpet and settle at the lowest point, under the spare wheel. Likewise, the aerial drain tube. If this is disconnected/wrongly sited it will drain any water from the aerial into the boot, rather than under the car as it should.

3) The fuel Filler gaiter, fuel filler latch box gasket and drain tube.
The fuel filler is another known water leak point. The filler flap is mounted on the top face of the wing rather than the side, which exposes it to far more water than most cars.

The rubber gaiter can be vulnerable to small rips/tears/holes if someone has cleaned out any debris too roughly in the past. A small hole here will let in a surprising volume of water. Again, any water entering here will flow down to the lowest point in the boot - under the spare wheel, leaving surprisingly little (if any) evidence of where it is from. Check the underside of the gaiter - is it damp?

The gaiter can also leak if it is not sealed properly round the neck of the filler tube. The gaiter is held on with a round spring clip, rather like a metal elastic band. If for some reason the filler box assembly has been disturbed (maybe a failed flap lock solenoid), then the gaiter may not have been properly seated, leaving a gap - or the spring band may be missing entirely.

A further way the fuel filler latch box can leak, is from its gasket. If this no longer makes a seal, water will be able to squeeze through between the latch box assembly itself and the body of the car, entering the boot. This would certainly happen if the four bolts have not been tightened properly (at least two of them are fairly awkward), the fuel box assembly has not been refitted quite straight, or if the gasket has been damaged.

Finally, the latch box drain pipe may not be properly connected. This would only allow petrol into the boot if you actually spill petrol when fuelling. Its main function if to drain water from the filler box assembly.
Water is channelled away from the filler box gaiter, down a tube which runs in front of the fuel tank (visible with the rear boot carpet removed) then out through the boot floor onto the ground. The tube is connected at the top onto the gaiter and held in place with a strong spring clip. It then exits out of the boot floor, through a grommet. If it is not properly seated at either end, water collected in the fuel filler box will end up in the boot.

4) Sunroof drain pipes. There are 4 drain tubes. Two run through the front pillars and out through the front wing splash guards, and two run through the rear pillars. The rear drain pipes then run behind the rear wheelarches and through grommets onto the ground by the rear exhaust box on both sides. The tubes can be seen easily with the boot's side carpets removed. The pipes have a yellow band round them - make sure they are pushed into the grommet far enough for the yellow band to be invisible. That way they are far enough in.

5) Rareish, but not unknown is a leak from badly sealed rear lights. Again, though it seems counterintuitive, the slope of the XJ40's boot floor means water entering here will end up under the spare wheel.

There are also a couple of rust related leak points on the XJ40. I strongly doubt your car has either of these since it is such a nice one.

6) Rust at the bottom of the rear 'D' pillar. The XJ40 is prone to rust under the D pillar trim, starting round the rivets which secure them. If a hole develops, it will cause water to enter the boot, or the cabin of the car, depending where the hole is. It tends to very obvious though, since swelling of the rust displaces the trim causing it to sit wrong. They're generally obviously rusty long before they leak.

7)Rust at the leading edge of the bottom of the boot floor, or the leading edge of the lowest part of the boot. If the bottom of the car has been scraped on the ground, rust can develop here, leading to a hole. Again, I do not see this as likely on your car.

8) Rust around the rear screen. Screen rust is nothing like as common on the XJ40 as it was on the Series I-III. It isn't unknown however, particularly if the screen has been replaced.


Another thing to check is that all the blanking plugs are present and secure.

Edited by dbdb on Saturday 22 March 12:15

[nta16]

dbdb said:

Very good advice! The XJ40 has really thick sound insulation which will hold an amazing amount of water.

that confirms to me that the soundproofing needs to be taken out of the car for it to dry out

the dehumidifier(s) are a great idea, you will need to make sure they are regularly emptied out as required

[PurpleMoonlight]

dbdb

Thanks for your detailed suggestions.

I had a look and fear you may be correct about water coming in around the filler cap area. It is very wet behind the boot lining there, but the corresponding opposite side is more or less dry.

I think I will book it into the local specialist. He can take the interior out completely, including the boot, and see what needs dealing with. There is a nice red carpet set on Ebay too which would look lovely in the car so I may buy that.

[Hooli]

Ahh red carpets. I really must get some new front ones for my XJ40, but I need to fix all those holes in the front wings & bulkhead first.

[LordFlathead]

I always leave a window down about a quarter of an inch, preferably on a side where people can't see it. If the car has a wet carpet I would removed and look to see if it has a rubber drainage bung. If it has I would remove that too.

If a car is going to kept outside for a couple of months you will be surprised how effective this is as a temporary measure.

[Flatinfourth]

nta16 said:

dbdb said:

Very good advice! The XJ40 has really thick sound insulation which will hold an amazing amount of water.

that confirms to me that the soundproofing needs to be taken out of the car for it to dry out

the dehumidifier(s) are a great idea, you will need to make sure they are regularly emptied out as required

If you choose your dehumidifier well you can get one wirh a hose connection from the water tub. With the dehumidifier secure and absolutely upright on a seat, The drain can be sleeved down onto a 1/4" brake pipe which can mould to the shape of a sill and door seal, thereby having a way out with everything shut and secure. that way there is little need to keep draining the tub, just leave the car for a eek or two!

[nta16]

if the car is outside don't forget to allow for frost damage, pipes that run outside can freeze up if not fully insulated (and in unheated garages too), if a pipe freezes it will not allow the drainage of the water and can back up to the dehumidifier, which also needs some form of frost protection