Early anitfreeze was bad for any metal. My father told me a story about when he put a 1939 Ford up for storage while he was overseas and filled the cooling system with antifreeze he pilfered from a Curtiss P-40 hanger. He returned to a pretty much dissolved radiator. Against every thinking mind set on the freeworld, I remove the 50/50 water antifreeze from all of my cars and run pure antifreeze. It will destroy cooling system parts if not changed? Baloney. I did that with a 1985 Nissan Sentra and I never touched any cooling system componet with 240,000 miles on the clock. Hence PERMANENT antifreeze. It's your money.

Bill