240 General: Wet carpet mystery

[146ken]

I know, I know, this is an old favourite but I've followed all previous advice on this topic and drawn a blank.
Briefly, early this week I had cause to check the fuses on my 240SE and found the passenger-side foot well was a bit damp, and in the rear foot-well was a good inch of water. Drivers side was dry as a bone. The water was clear and seemed fresh, that is things hadn't started to fester and smell damp. This morning I've stripped out the carpet and foam underlay and dried things out.
I then started pouring water round all the likely points of entry. The sill drain holes were good and clear, opened the plastic grommets on inside and the sill is clear of debris and blockages. I've checked all the rubber plugs in the foot well and they are intact and watertight. No leaks on sunroof, and the doors appears watertight.
The carpets were sodden at floor level but dry above which seems to point to a leak at or around floor level but I can't see any obvious entry point.
I've come to the conclusion that the gale force winds early in the week have forced the water in somewhere. The car was parked heading into the gale and torrential rain.
Any thoughts or pointers to what next would be well appreciated.

[Paul Clifton]

Most likely water entry on 200 is 1. windscreen 2. grommet where wiper motor goes through bulkhead or 3. from behind 'tar paper' sealing behind trim and fusebox, this is where the heater air intake grills are drained. The water runs between the outer wing and inner footwell panel. ......if there is any dterioration of the sealing behind the fuse box water will enter at floor level.

Paul.

[Alec Dawe]

Another thing to check, and this is direction sensitive, is are the footwell vent flaps open. It has been known for driving rain to get into the car that way, through the ventilation flaps, and/or their seals

[Clifford Pope]

I've never really understood the precise function of the tar paper. It certainly isn't the seal between the heater vent drains and the inside of the cabin, because even with the decayed paper totally removed I can pour water down the vents and not a drop enters the car. This seems to run down an entirely hidden duct between the side of the bulkhead and another "false" partition.

If there is a rust hole in the metal between the inside of the door post and this duct, water can run down inside the door pillar. That leads to a) more rust, and b) ingress into the fuse box area and so the floor of the car, if the paper is not intact. So the paper seems to be merely a way on concealing water entry, rather than an intended first line of defence.
I for one would welcome a really expert explanation of how this drainage system is supposed to work.

There seem to be several entirely separate mechanisms for water entry:
1) Leaks in windscreen surround or wiper grommet. Easily detected with a watering can.
2) Leaks caused by the drainage holes in the sill being blocked, so that water draining down the ducts backs up and spills over into the car - exacerbated if the plastic plugs are missing or the holes rusted.
3) Leaks caused by rust holes in the drainage duct or door pillars, letting water through where it shouldn't.
4) Leaks that only occur when driving, when rain is driven backwards up over the windscreen lip through a faulty seal, or through the door seal, or possibly through the ventilator flaps in the footwell side panels, if fitted.
5) Blocked sun-roof drains. I think this only applies to the genuine kind of sun roof, that winds away into a slot in the roof. I believe this has chanels that run down the B-posts? The other simpler after-market kind, that just have a sheet of glass that hinges tight up against a seal, I don't think has this kind of drain, just a flat glass to rubber seal. If it leaks, it drips inside.
6) Other mysterious leaks, that seem to have no explanation!

[Mike_Brace]

One that is harder to check - I have come across corrosion of inner sill letting in water under raised area where seat is. I would remove carpets and leave without for a while and see if there is any further signs of water entering. It will naturally tend to flow from front to back under the seat where the cables run. It is also possible for water to run down the inside of the door and if the plastic is not sealing to run between the door and trim panel and into the car that way.

Mike

[146ken]

Thanks for hints. Tar paper seems intact and dry.
Having got everything as dry as possible I've found the leak, or rather narrowed it down to somewhere around the seat belt mounting at base of pillar, or close by in the bit under the raised section alongside seat.
I guess with the seat removed I can find it exactly, hopefully we are in for a dry spell.

[PTJS]

On my 1988 240GL part of the electrics loom passes from the engine bay through the bulkhead on the passenger side and can be a leak problem. Also, under/around the wiper motor position as seen from inside the passenger footwell, you will see two rubber grommets - make sure these are present and intact. I had a leak problem from one of these which had been cut to pass an alarm cable through and water got in through it and wet the passenger footwell - and the rear of course because eventually it flows to the rear to create indoor swimming pools.

Just as an aside, I have a continued leak around the bonnet release pull on the drivers side. Have duct taped around it - no joy, then stripped the tape off and put mastic around it - again does not seem to have worked. Now trying a bright idea of using a piece of flashband, the stuff you seal splits in flat felt roofs with. Will cut a square of it, then cut a slot, peel off the backing to expose the bitumen layer and then slide it around the release pull and work it to ensure it sticks right up against the junction of the pull release and the bulkhead. If this doesn't do it I shall be very disappointed to put it mildly. Its a real pain drying out those sodden carpet underlays every time, isn't it!

Good luck

Phil

[146ken]

It is a right pain drying out carpets etc. I was considering turning the rear footwell into a water feature, maybe a wild life pond.
Located the leak though. Base of central pillar is a plastic cubby hole in which sits the inertia reel; the seal around this had perished and water poured in there as much as out of sill drain holes.
I guess this can be fixed with some all purpose silicon sealer, which is what I"m going to try first, unless anyone has better idea or experience with this one.
Mind you its raining again now so its on hold.

[PTJS]

Try the flashband. It seems to have done the trick with my longstanding problem and .... it will never come off!

Phil

[Mike_Brace]

The best sealant is the one designed for the job - car body sealant.

Mike