Hi, has anyone experienced this or have any suggestions please? 2004 TD5.
On my way home tonight I had a couple of drips of water land on my left knee as I turned left into my road. Inspected headlining etc. first of all and that was all dry, then noticed a trace of water just below the driver's side middle heater vent and a drop on the centre console.
I've been noticing an intermittent trickling noise from behind the dash lately (2 weeks or so). Have bled the cooling system after it was incorrectly part-filled, and continued to let out the odd pfff of air from the bleed screw. Some days the trickling noise is there, some days it isn't. No overheating or even hot engine smell, no coolant loss, heaters nice and hot.
I'm gathering from internet searches that the problem is actually with the heater matrix. And that accessing it is a major job.
Am I on the right lines?
Is there a way to fix this that doesn't involve removing the dash? Any experience much appreciated

First off you need to check what kind of water you have on your knee ...... sounds daft, what kind of water .... I know.
First answer it's "wet water"!
So having got the frivolities out of the way, does it have coolant additives such as anti-freeze in it or is it clean?
If it's clean then your problem is the little drain pipes from the air con are probably blocked; there's one each side of the gearbox on the underneath of the floor.
If there's anti-freeze in it then I would suggest that you have a small leak in the heater matrix.

I'd have thought that the heater matrix was too low in the dashboard to get water up onto your knee?

It sits just above the transmission tunnel so quite low down.

Leak through the sunroof and down through the winder mechanism possibly.

Peter