98 F-150 Severe Coolant Leak (cross posting to 3 groups for max coverage)

I have a friend that has a severe leak on the rear of her engine. I mean as fast as a water hose can put water into the expansion tank, it comes pouring
out somewhere on the rear of the engine.
Its a 98 F-150 ext. Cab with a 4.6L A/T. Its got about 150,000mi on it.
I am good with cars, hell I worked on the Ford hotline, so I know what to look for, but what I am looking for here is if anyone has seen this before. I know full well it could be a bad freeze plug (what I am leaning towards), or a cracked block, or better yet a corroded heater line coming off the back of the engine. The reason I am checking here, is to see if anyone has seen this before, because you have to pull the engine to be able to see it, or remove everything down to the lower intake. Either way, its more than I want to do so I can diagnose her engine problem. I am looking for people that have worked on a specific case that matches this one.
I found the original source of the problem, I think the engine overheated due to low coolant level, and inadequate coolant mixture. She has a leak on the air purge between the top of the radiator and expansion tank, and she let it get low a couple of times, and didnt put 50/50 mix back in it.. Just water. So I think the truck boiled the water off inside the block and either blew a freeze plug, or cracked the block. Either way, since you either have to pull the engine or trans to get to the leak, she knows its not goin to be cheap to fix. My experience with this engine is limited, so any body who has seen this before. I would appreciate the input.
Thanks, Ford Tech
P.S. I am only looking for techs that have worked on this problem before, not input as to what you might think it is, due to experience on a different engine ( I have that experience), only this engine, and only with the metal heater lines running out the rear of the engine. Thanks
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On Fri, 30 Mar 2007 11:35:06 -0500, "Ford Tech"

What about the heater tube that runs under the intake from the back of the water pump. Does that one not have it like the CV? Any water leakage from that runs back under the lower intake on top of the block and off the rear.
Lugnut
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wrote:

See I was lookin at them lines, but I couldnt see where they went after they dipped behind the engine.. Damn thing sits half way under the cab back there.. So it litterally runs all the way under the intake up to the water pump in front huh? Well i will have to take a closer look at that...
Thanks. FT
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