Bad coolant leak

[Thebrit]

So, I have an 05 Land Rover LR3 with the V8 Gas (petrol) engine and 235.000 miles.
There is a serious leak somewhere behind the engine. I've tried to see where it is using a flashlight and a mirror but to no avail. The water comes out almost as fast as I fill the reservoir with the engine not running but curiously I see nothing with the engine actually started. I've read about the valley gaskets being a potential issue but why no leak with the motor started ? I have checked the hoses to the heater core and they are dry.
Thanks for looking and thanks again for any light you can shed on the issue.

 

[jeremyderek]

It doesn't look like you ever received any help here, but I'm having the same issue. Any chance that you figured out where it was coming from, or perhaps a 2 year late bump will get someone's attention who knows.