For Focus

Hi, I have a 2003 ford docus tddi 1.8 litre diesel car. Basically the water in it is leaking although I cant seem to figure out why. Ive changed the water pump and the thermostat in it and it hasnt helped. I recently took the two pipes off the egr valve and connected them upto a piece of copper pipe and it stopped the leak, although the turbo charger also went when I had this done (i dont know if it went because the egr valve was bypassed by it was expensive for a new one so I dont want to rick it). I replaced the egr valve yesterday and now the leak is back, so it seems that the valve itself isnt leaking but its having something to do with the leak. Any help is much appreciated!

Conor.