I began working on cars in 1970, in Ft. Lauderdale. Just about everybody thought they were smart and saved money by not using anti-freeze since it never gets cold there. Duh. Stupidest thing you can do. Oxygen causes corrosion, right? Water is 33% oxygen (H20...) Anti-freeze not only prevents freezing it also contains additives to protect the system, such as heavy metals that act as sacrificial elements which take the abuse instead of the cast iron. What exactly do you think it was that plugged up your radiator?Iron particles. aluminum flakes, etc. - that's what. That's why you should either replace the anti-freeze every two years, add an additive package or use a water-free product. (like Evans)

Electrolysis is another huge cause of cooling system corrosion. Automakers have been paying attention to this for the past thirty plus years. If you're old enough you can probably recall having to change radiator and heater hoses every few years. These days very few can recall the last time they had to replace a cooling hose, even if their car is twenty some years old! It isn't that the rubber is 'new and improved' or some form of polyrazzmatazz. It's because the automakers figured out it was cheaper for their warranties if they paid attention to the system grounding. For more info read: electrolysis

 

I have always used antifreeze and since I don't know how often the previous owner changed coolant, I'm sure this along with age was clogging the passages. The new radiator is on and everything is back to normal so far.