Bring the coolant all the way up in the expansion tank, fill the overflow
tank to the minimum line. If the water/coolant ratio is right - 50/50, the
coolant mix will expand due to the heat of the engine as it passes thru,
and expanded  heated coolant mix open the port in the expansion tank cap
and will overflow into the expansion tank. If there is to much coolant mix
in the overflow tank to start with, the excess overflow from the expansion
tank will be fored out three little ports on yhevupper back side of the
expansion tank. The whole system is built around expa nsion and contraction
of water as it heats and cools, and upon 5he weight of air at atmospheric
pressure. Basic physics!

John
On Apr 26, 2016 13:21, "Dan N" <dn92610@gmail.com> wrote:

> Neil,
>
> he said that he gives room for the coolant to expand... I told him when the
> coolant expands the blue cap will open and the coolant goes to the
> expansion tank behind the license plate...
>
> he didn't buy it...
>
> I am sure he's thinking as modern car with the radiator and a filling tank
> with no pressure cap and no expansion tank..
>
> haha...
>
> :-)
>