X308 Water leaking into drivers footwell.

[Thin White Duke]

I got into my car today after not driving it since Saturday. After a round trip of 14 miles
I got out only to find my right shoe wet through. I looked and found about 1/2 inch of water in the footwell
as well as water dripping from underneath the dash (the area where the peddals come from).

Does anyone know what it may be before I start poking around?

Could it be the windscreen seal, drainage tubes blocked up or something from the engine bay?

[Straight6DOHC]

Remove the 17mm nut from the windscreen wyper and remove it. Remove the 5 torx screws from the trim that the windscreen washers attach to. That will give you access to see if the lower edge of the windscreen where it's bonded. You might also see a puddle somewhere along the lower edge of the windscreen - or clues to possible ingress. On an x300 the ecu is situated at the right of the driver's foot, in the wing, and can suffer from water ingress which damages the ECU. At present - as far as I'm aware, no-one really know how water gets in but there are a few theories.
Have you had a lot of rain recently, have you a sunroof and have you lost coolant? All these questions may have a relevent answer regarding water ingress. There are a few holes through the bulkhead so again check all grommets. You know those 5 torx screws I mentioned earlier? If water gets in those holes, where will it end up?

[Straight6DOHC]

Forgot to say, check your plenum chamber's drains are not blocked.

[Thin White Duke]

Straight6DOHC said:

Remove the 17mm nut from the windscreen wyper and remove it. Remove the 5 torx screws from the trim that the windscreen washers attach to. That will give you access to see if the lower edge of the windscreen where it's bonded. You might also see a puddle somewhere along the lower edge of the windscreen - or clues to possible ingress. On an x300 the ecu is situated at the right of the driver's foot, in the wing, and can suffer from water ingress which damages the ECU. At present - as far as I'm aware, no-one really know how water gets in but there are a few theories.
Have you had a lot of rain recently, have you a sunroof and have you lost coolant? All these questions may have a relevent answer regarding water ingress. There are a few holes through the bulkhead so again check all grommets. You know those 5 torx screws I mentioned earlier? If water gets in those holes, where will it end up?

Great advice and I think me and my old man have solved the problem.

I did notice last week when I had the car washed and I used the air con a few hours later that there was a gurgling noise. I didn't think anything of it until todays situation.

We did take all the trim and panels off and found water lodging in the central bay, the plug having been sort of blocked. We took the plug out and the water drained away.

I can only think that this plug is to prevent possible engine fumes from entering the cab when the air intake is on - I haven't therefore re placed it. I'll see how things go over the next week or so, but I think the problem is solved.

We have had a lot of rain, but I think it was the angle at which the jet washer blasted the trim area from that caused the problem.

[Touring442]

These cars - in common with the XJ40 - can rot in the bulkhead. You'll need to pull back the sound deadening trim panel whereupon you may well find some nastiness - it's a long, long time since I saw one do this (an early X300) so can't recall the exact details, but it was holed quite badly and an earth strap 10mm fixing point had rusted off. The hole allowed water in where it also made a mess of the floor.....