[C320-list] Coolant Levels

[Stephen Cox]

> My coolant overflow has been bone dry for years. I noticed 
> the overflow container is below the heat exchange opening 
> where the tube runs from just under the cap to the overflow. 
> Even if I fill the overflow to the minimum level as indicated 
> I don't see how it would flow back into the heat exchanger. 

Overflow bottles work as long as you have the system topped right up at the
cap with no entrapped air in the line.  When running and hot the coolant
expands and the level in the overflow bottle will rise.  On cooling the
coolant in the engine block contracts and the partial vacuum sucks back
whatever extra coolant it needs.  

Stephen Cox
Tegwen #1141