Background: The front heater on my Land Cruiser doesn't work and I spend some time diagnosing it this weekend.  As it turns out, the previous owner has completely bypassed the front heater core.  From what I have read on the Land Cruiser forums, the heater valves on the FJ80s have a tendency to get out of adjustment and fail to close all the way (meaning there is a constant flow of coolant through the core, which is a big problem here in AZ in the summertime when you want maximum AC).  It looks like the previous owner didn't know how to adjust the heater valve and simply decided to disconnect the front heater core. 

So here's the question: Do yo think I can just reconnect the front core?  I don't know how long it has sat dry and unused, is there any risk that the lack of use has damaged it (I am thinking corrosion or something)?  Is there any harm in just hooking it back up and seeing if it works?  If I do that, should I try to flush it first, to see if there is buildup in there that I should try to keep from getting into my cooling system?

Any insight is appreciated.  I really want to avoid replacing the core if I can, because that requires major dashboard surgery.