I recently inherited some early cars from my father who passed last year. They were in a heated garage. In two brass cars he used water in the summer with a Napa corrosion additive and kerosene in the winter as they were not driven. In a Flathead Ford he used water and the Corrosion additive but in the winter he just drained while the engine was hot. My building is not heated and will freeze in the winter. He did not used anti freeze due to the babbit bearings which can be destroyed by antifreez
I have done some reading around coolants.
Propylene Glycol is only used because it is less toxic than ethylene glycol. It is less effective as an antifreeze. Propylene glycol oxidises when exposed to air and heat, forming lactic acid. It must be suitably inhibited to prevent corrosion. Biological fouling also occurs with PG.
The ONLY evidence I have been able to find about Organic Acid Technology (OAT) and Hybrid OAT (HOAT) causing problems was with coolants containing 2-