2.7D 2007 huge coolant leak at rear of engine
 

Hi Guys, My S-Type has been limped into my mechanic with a huge water leak from near the top back of the engine. My mechanic has said he cannot access or see where the leak is from the underside, and is loathe to get too carried away stripping the turbos etc off the top to get to it.. Does anyone know what the leak is likely to be ie are there any specific hoses etc up there like heater or intercooler pipes that are known to go on these? At least I can then give him a nudge in the right direction...
Many thanks guys.. to give you an idea when I say huge.. if the engine isnt running it seems to settle after a short while, but as soon as running the coolant goes from full to the coolant reservoir drained in approx 0.5 miles.. so my gut says a hose, but I don't know what is at the top back of the engine or even if there is any known common failures that would give these symptoms/seeming location..if it is any additional help at all (which I doubt) on the last section of the journey into my mechanic steam was rising off the rear of the engine and fogging my windscreen..The journey to my mechanic this morning involved over 10 stops over I guess a 5 mile journey and I had over 70 litres of water in containers I worked through to manage that distance.

To move forward a little my mechanic has just called and tomorrow is planning to remove the air con pump to see if he can gain access without removing the turbos. He paused doing this as his air con recharger has packed up so I will need to re gas it myself after everything. He says the leak is very close to the rear of the block it isnt as far back as the heater pipes.. But that is all the info so far..

I have been looking around and can find no mention anywhere as to if the 2.7D has a valley pipe as that would explain things..

may be try posting this or searching over at the UK forum , there seems to be a lot more diesel S types over there .
sorry for my lack of help .