[Dave B.]

First it was unleaded gas, then zinc-free oil. Now it's OAT (Organic Acid Technology) antifreeze. The quick and dirty story here is that OAT (as opposed to the older IAT - [Inorganic Acid Technology]) antifreeze can attack both silicone-based gasket sealants and - more important - lead-based substances like radiator solder. Some antifreeze producers have been quietly phasing in these products without any warning labels to owners of older cars.

So, without any more wasted bandwidth, here's a short article that does a pretty good job of explaining the problem. Also note: there are clickable links within the article.

https://www.ncregionaaca.com/firstcapital/index.php/old-cars-and-antifreeze

 

[kevin temple]

Thanks Dave for info. My '64 6 cylinder water pump just started to leak, looks like at gasket, not pump bearing. I replaced water pump with a Napa pump 4,000 miles or 4 years ago. I have been using green extended life coolant in Nova for years. Going back to green original coolant. Change it every 2 years.

 

[67 Nova Boy]

I use Peak...50/50 has NHRA on Blue container. Says long life on front...good?

Dave