I seem to be losing water from my 92 discovery TDI, not a great amount, but
I have put in
about 3 litres in the the last 2 months. I can't find any signs of the leak
anywhere in the engine
bay, the heater doesn't appear to be leaking, there doesn't seem to be
anything untoward
in the header tank and no visible smoke from the exhaust. The car does not
overheat, but
the temperature gauge does climb a bit higher than normal before the
thermostat opens
for the first time (probably always has, but i'm constantly watching it
now).
I am open to any suggestions as to what the problem is.

I also noticed a couple of other things in my hunt for the elusive leak, I
would like the
groups opinion on.

1) A mystery small bore plastic pipe with a "U" bend on the end, which was
laying on
   the oil filter. I assume this is some kind of breather pipe as I cant
see where it could
   attach to. ( It seems to run from somewhere near the gearbox, but it was
too cold
   to get underneath to check).

2) A spare connector on the alternater. I assume that! it is just unused.

Pictures are here http://uk.pg.photos.yahoo.com/ph/stewith/album?.dir=/a12c
if anybody would like to look ( one is out of focus, but as I said it was
cold and I was
shivering when I took the pics).

Thanks in advance for any assistance.