Water leaking behind block

I have a massive leak at the back of the head on my td5 discovery. When i fill water into it, its coming out as fast as it is goin in. Any help is gratefully appreciated. Thanks

Probably core plug rusted out.

Use a mirror and a torch to see better, bounce the beam off the mirror, bad light (dusk) sometimes helps the viewing experience.

Don't know if this will solve it but I give you my story of today. I removed the EGR 6 months ago when I got my defender td5. i began at some point notice a small diminishing in the expansion bowl and started to trace just to find the metal pipe running behind the engine, EGR cooler pipe, had a a small hole from the heat shield rubbing into it. It sprayed some on the side of the block which now was pretty red from cooling fluid. I did a lot of research and there is at the end of the day very little solid info on the forums on this one. But now I can with confidence tell that this is the way to go to diminsh problems in the future especially if your engine is an EU3 and later which makes this mod easier to do. If you remove EGR do remove the complete EGR cooling system along with it. Make a plug from a bolt and hose to block the oil cooler outlet (this is possibly where you have the leak as it seems to leak a lot for you and this is a common failure spot). Remove the metal pipe running behind engine by undoing the two bolts, they are tight as they are the transmission connectors to engine. Remove the EGR heat exchanger (3 bolts), possible without removing the fan, remove the pipe running from heat exchanger to 4 way connector and block it off at the connector. Now you have got rid of several potential leaking spots, made bleeding the water system a joy. Finally block the exhaust where the EGR used to connect to the exhaust manifold with a plate you can purchase separatey and you are set. This might solve your leakage if the leak happens to be anywhere along this line.

Check the oil cooler outlet to the pipe that runs around the back of the engine. There is a short length of rubber pipe connecting them and it sits under the rurbo and fails after a few years hard work, On later models the pipe is actually a short bung and the oil cooler to pipe is not connected, but the rubber bung fails, a silicon bung is available on the bay for a few quid.

Cheers