It makes sense. The previous owner replaced the radiator. If there was gunk in the radiator/engine, and it was a severe enough problem, gunk probably got into the block. Replacing the radiator only "bandaided" the issue at the time, and since the radiator could flow again, the problem was temporarily fixed.
However, there was crud still in the block. So over time, as the radiator began to build up gunk again, and with the gunk in the block possibly migrating through the system, the original problem surfaced again, this time with us.
Replacing the engine (this was due to work on the engine to correct damage done by the overheating, in other words replacing the seal and correct a small warp issue, and they put in the crankshaft crooked and then it breaking) only fixed "part" of the problem again, as the problem with the system that acutally cools the water (the radiator) still existed.
This also combined with the fact that the water pump leaked (as was so corroded and ended up corroding the timing belt so bad that it actually rotted a new timing belt when the motor was replaced within a three month time period)and gunk was found in it, reinforces the fact that there is gunk in the system.
Other half is gonna take a look at the bottom of the rad (if there is that much gunk in the system, then there should be some signs of it there as there were signs of sediment in the overflow tank) and I think we are gonna get an aftermarket one. Comparing the price for a rad flush ($70) vs the price of an aftermarket rad ($100-$125 and pretty easily put in ourselves) its gonna be a new radiator.
Unfortunately since he's a truck driver, its gonna be at least a week before he's back home! Will let ya know when we get this done.
Lets hope this is the end of this issue. The car is a good car. It might be older, but you can't beat the fact that its paid for and insurance is low on it! And the fact, who wants to steal an older car, in a town that has high auto theft!
Again thanks for the info.