I found the following on the web. It’s the way I remember antifreezes and common practice at the garages I worked at.
Through the mid ?70s, most antifreeze contained silicate additives which were abrasives that kept the mineral deposits, in the water, from building up in the cooling systems. Because the silicate additives were abrasive, they also destroyed water pump seals. A water-soluble oil was added to the antifreeze solution to protect the water pump seals. This oil was called water-pump lubricant.
If you used straight water in your cooling system during the summer months (distilled water worked best) you also had to add a pint of rust inhibitor/water pump pump lubricant to the water.
Joe