Does the coolant overflow need to be a closed system

[Classics Fan]

Originally Posted by Rust_never_sleeps

Those that have done this, what's the approximate volume required for this kind of setup?
Presumably less than 750ml, since a JD bottle works ;-)

Dorman makes several styles of coolant recovery bottles to fit almost any vehicle. I’ve installed several on my 60’s and early 70’a vehicles that were originally open systems and allowed overflow to go on the ground. Another advantage is the radiator stays filled right up to the neck compared to the open systems where the top inch or so of the radiator is not filled, exposing that area to oxidation and corrosion.

To answer your question, approximately a quart of coolant is what I see in the bottle.