Land Rover Repair: Coolant leak, intake manifold gasket, coolant leak

Question
I have a '99 Disco II and I have been refilling the coolant reservoir bi-monthly the entire winter.  Until this past weekend I have not seen any leaks whatsoever.  When my heater would start to run cold I would top off the coolant and it would be fine again.  Now, as of Saturday, I am seeing a leak coming from what appears to be somewhere on the top of the block very close to the firewall on the passenger side (I'm in Utah so it is standard passenger side).  From the top of the engine looking down I can only see a trickle on the side of the block coming from somewhere above, I presume. I am having difficulty seeing anything else on top of the block because it seems as though the block begins to sit back under the firewall thus hindering my view.  The vehicle has 120,000 miles on it currently.  Are there hose in that area that commonly go bad over time?  Could it be something other than a leaky hose?  It only seems to leak when it is at certain operating temperatures.  Any help would be much appreciated.

- Jeremy

Answer
You are going to have to find someone who can pressure test the system to be sure, but you probably have a leaking intake manifold gasket (1 day job) or leaky head gaskets (2 day job)

If the head gaskets leak I strongly suggest surfacing the heads and doing a valve job at the same time.