A few years ago I ran up on a great sale (under $5 per gallon as I recall, sale was aimed at commercial accounts) of Peak Long Life 5 year / 150,000 mile concentrate coolant. At the time, with two MCs, 2PUs, and 5 cars that were liquid cooled, I bought 3 or 4 cases. It is designed for all cars & all MCs and all vehicle cooling systems. It is yellow, it is silicate & phosphate free too.

https://peakauto.com/products/antifr...full-strength/

Today, checking to make sure it was OK in my Fords (and it is as I thought), I looked it up too and I see in a spec sheet they mention a shelf life of 3 years in an unopened original container, of which I have probably 25 left, though I have sold some of the vehicles and MCs.

So my question is:
How does … a concentrated coolant product …
last longer … mixed with distilled water @ 50/50 or 60/40 in a cooling system …
than it does … in an unopened sealed original container in cool, dark, basement shop storage ????

I sent a query, no answer yet.

I know from past reads here, some of you will know.

Thank You.