rust in water

[pooch]

Originally Posted by Cornishman

Rust is not caused by water, it is caused by oxygen and warmth. Any part of the iron internals will rust if it is exposed to air. Iron and steel submerged underwater will oxidise but more slowly than those exposed to the atmosphere. It is quite likely that rust has formed where there has been an air space in the engine. Antifreeze and other inhibitors prevent the oxidisation caused by water.
For my information: What is soluble oil? It's not something I've heard of before reading this thread.

Easy to detect , look down the hole and see white, it is soluble oil.

I have not used it for years but I wonder if it would not put the greasy stinky scum on your windscreen of your model A as does coolant in an unpressurised system .