Got to talking w/ my bro-inlaw, who runs a full service station. He alerted me to the heater core problem...said about 100k mi or so was the time to expect problems, and yes, the entire dash must be removed....last time i had that problem was with a '57 Tr3 (Triumph, for all you youngsters) when my legs got flooded with hot water on the way home from Tahoe one night. Had to open the doors to let the water out. By the time I got to a gas station I was numb from the freezing effect of the cooling water soaking my skin, and this was in the middle of the winter. Bummer......
Good luck with it if you do it yourself. You'll save about $800.

 

I just replaced mine (210k) it took about $35 and 20 minuets. 88 f-250