Loss of water TD5

I have a Land Rover Discovery 2 TD5, I keep loosing water at a rate of about 1/2Lt each week. I can't see any sign of a leak under the car or inside. The oil looks clean and I have no sign of steam out the rear. I have replaced the filler cap on the header tank, and heater matrix.

Any ideas??????

You could check the carpet around the transmission tunnel under the dash, it could be a heater mattrix leaking, failing that......head gasket, you dont always see vapour pouring out the back as it could only be under load, i.e whilst driving. Your CATS will absorb a fair amount initially which is why they will also require replacement if it is the HG. Not good news I'm afraid.

after going for a drive, squeeze the coolant hoses. If they are rock hard then start suspecting headgasket.

Otherwise......

are there and sticky or chrystal like residues on the connections of any of the coolant hoses. These signafy a leak.

Check the fuel cooler is not leaking at the end caps,

the top hose where it meets the cylinder head (pipe with bleed screw in it)

also bottom corners of the radiator where the ali matrix meets the plastic end caps.

It does not take much of a leak to loose quite a bit of water, and the OAT coolant boils of quite quickly, so can be difficult to find.

the radiator end caps can leak also look look for red staining on the radiator fins

i've got a 200tdi and i've had trouble with loss of water recently and on inspecting mine i found that the water pump has a slight leak and half my radiator finns are missing.like you i would top the water up go on a drive then check the water when i got back and 50% water was lossed and the back of the rad was very wet.
im replacing my rad,thermostat,water pump and gasket then hopefully that should be it sorted.
have you checked the back of your rad for leaks and checked the finns?
hope you get it sorted soon.

atb lee

Many thanks for all the advise, I will check out all the suggestions and keep you posted. I will do some serious miles in the summer with a caravan on the back, I can't afford to run dry. It's strange a light comes on when the washer bottle is empty, but if you run out of water nothing!!
once again thanks